13th Black Crusade (Original)

"Thirteen times shall the Traitor King go forth. In the End Times the iron fortress shall be cast down. Its walls breached and its Gate forced open. Those that dwell beyond shall spill through it. The air shall burn and the ground shall melt, The Daemon shall lie down with the machine, Brother shall slay brother with fire and sword. And the sky-wound shall pour its malice forth. The Eye shall stare unblinking at its prize, and the Traitor King shall cross the bridge of stars. He shall return to finish the Warmonger's red work, Upon holy soil shall the fate of man be decided."

- The Liber Malefact

The 13th Black Crusade of Abaddon the Despoiler that began in 999.M41 resulted in the largest mobilisation of both Imperial and Chaotic forces seen in the Milky Way Galaxy since the Horus Heresy. During this campaign, at least one of the remaining Blackstone Fortresses still in the hands of Abaddon the Despoiler was destroyed by Necron raiders since they were weapons crafted by the Old Ones that were originally intended to destroy the Necrons' Star Gods, the C'tan.

The 13th Black Crusade was the in-game background to the worldwide Warhammer 40,000 Eye of Terror Campaign. It resulted in a minor victory for the Forces of Chaos and gave the Warmaster of Chaos Undivided, Abaddon the Despoiler of the Black Legion and his Chaotic allies, the territorial foothold they had long sought within the Cadian Gate, though he suffered grievous losses to his naval warfleet.

While the surface of the Fortress World of Cadia is now largely controlled by the Forces of Chaos, the skies above Cadia are almost entirely ruled by Lord Admiral Quarren and the Gothic and Solar Battlefleet Groups as well as fleet elements from several Chapters of Space Marines, leaving the ultimate result of the 13th Black Crusade a stalemate as the battle between the Imperium and the Chaos foothold on Cadia rages on. Having both space and air superiority gives a significant advantage to the Imperial forces, allowing the deployment of fresh troops and the continuous bombardment of Abaddon's trapped army on Cadia as the 42nd Millennium began.

Gothic War's Outcome
"Like the great storm of the Heresy, the forces of the True Gods will descend upon the False Emperor's minions. The stars will tremble at their passage, the mighty armadas of the Warmasters will bring annihilation to a hundred worlds. Great shall be the slaughter, most pleasing shall be the flow of blood. The fools who follow the Emperor will be brought low, forced to their knees amidst the corpses of their families and friends. The thrice-cursed one shall become as a living god, the power to destroy the Weakling Emperor shall be within his grasp. Know this, for these things will come to pass and the galaxy itself will be the spoils of victory."

- Constanze the Prophetess, burned as a Heretic, 356.M38

To understand the full course and impact of the 13th Black Crusade upon the galaxy, it is first necessary to retell the tale of Abaddon the Despoiler's 12th Black Crusade, better known in Imperial records as the Gothic War. Like many sector-wide conflicts with the Archenemy, the Gothic War began slowly, with sporadic Chaotic raids against smaller Imperial outposts in the year 139.M41. Vessels whose crews had been stricken with diseases sacred to the Plague Lord Nurgle were discovered adrift in the Athena Sector of the Segmentum Obscurus, along with sightings of the Chaos warship Plagueclaw, and Astropaths began reporting unsettling disturbances in the Warp that slowly cut off the Gothic Sector of the Segmentum Obscurus from the rest of Imperial space. Panic and anarchy became widespread in the Gothic Sector as fanatical religious sects arose, believing that the Emperor was displeased with them. Hysteria spread throughout the sector and on many Imperial worlds order broke down completely. The Imperial Navy lost several starships to "accidents" in space dock that were subsequently blamed on poor maintenance and faulty ammunition -- a rather too convenient explanation for many. Three standard years after the first Chaos raid on the Imperial listening post at Arx, in 142.M41, the forces of Abaddon the Despoiler, the Warmaster of the Black Legion and leader of the allied forces of Chaos Undivided, struck out at the Gothic Sector from the Eye of Terror.

Abaddon's Chaos warfleets struck at a dozen Imperial bases and sent the warships of the Imperial Navy's Battlefleet Gothic reeling. Chaotic starships attacked all across the Gothic Sector and the first inkling of Abaddon's true intentions in launching the 12th Black Crusade against the sector was to come to light in the Rebo System, where one of the mysterious xenos Blackstone Fortresses orbited the fifth planet. These massive edifices of unknown alien origin had been refitted by the Imperium to serve as orbital bases for the starships of Battlefleet Gothic. For the first time in the history of the Imperium, one of these fortresses fell to Abaddon's forces and he was soon to make horrifying use of the captured base's advanced alien technology. Abaddon's fleet possessed a devastating weapon, never before seen by the Imperium in the hands of the Forces of Chaos, called the Planet Killer. Its name was not simply born from the arrogance of its Dark Mechanicus builders, but was a well-deserved epithet as Abaddon demonstrated at the Cardinal World of Savaven. The account of the utter destruction of Savaven as witnessed by Jeremiah Soldagen, Savaven's orbital defence commander, still has the power to chill one's soul. His description of entire continents splitting apart, burning skies and the planet breaking up into pieces is solemn reading. Fourteen million people died within a single hour and the crippling effects of this on Imperial morale at the time should not be underestimated; many worlds were hurriedly -- though unfortunately not always entirely -- evacuated before the Planet Killer arrived.

Another Blackstone Fortress fell to Chaos at the world of Brinaga. At Fularis II, Abaddon was to demonstrate the true power of these ancient xenos constructs. Exact information regarding the incident remains sketchy in Imperial records, but the evidence points to a massive energy beam being unleashed from the Blackstone Fortress that scoured Fularis II bare, stripping its atmosphere and transforming its surface into a barren, rocky plain.

Imperial forces were continually engaged throughout the Gothic Sector, from the Hammerhead Deeps to the Cyclops Cluster, desperate to halt the might of the Chaos warfleets' Black Crusade. At the beginning of 151.M41, Lord-High Admiral Cornelius Ravensburg, the Imperial Navy flag officer in command of Battlefleet Gothic, took the fight to the enemy, resulting in the clash at the Battle of Gethsemane where he was able to utterly destroy a Chaos warfleet of considerable size. Eldar vessels also fought in this battle. Though many Imperial historians believe their role to have been minimal, the evidence indicates that the Eldar's involvement against the Forces of Chaos were considerable during the latter stages of the Gothic War through the use of their Webway Warp Gates.

News of this great victory invigorated the Imperial Navy and as the Warp Storms that had isolated the Gothic Sector for over a decade began to abate as the Dark Gods grew wrathful and capricious at their forces' defeat, Imperial vessels from neighbouring sectors were finally able to reinforce the Lord Admiral's bloodied Battlefleet Gothic. Abaddon then brought the full power of the Blackstone Fortresses he had captured to bear on the star of Tarantis, the mustering point for the new Imperial starships entering the Gothic Sector, in an attempt to stem Battlefleet Gothic's reinforcements. Combining their power, the Blackstones destabilised the Tarantis star and caused it to go nova, destroying everything still within the star system in spectacular fashion.

The final battle of the Gothic War was fought at the world of Shindelgeist, where the Imperial Blackstone V still floated in the depths of space. A trap was sprung by the Lord Admiral and the Eldar, who defeated Abaddon's greatest warfleet in a truly magnificient three-day-long battle. In an act of spite, Abaddon sought to destroy the star there also and had it not been for the sacrifice of Captain Abridal on the Flame of Purity, the victory could have been a hollow one. Abaddon had been defeated, though he escaped back into the Eye of Terror with two of his captured Blackstone Fortresses, though various sources claimed at the time that they must have been destroyed. Unfortunately, as the 13th Black Crusade would demonstrate, this was merely wishful thinking on the part of the Imperium.

Plague of Typhus
As the end of the 41st Millennium drew closer, the first signs that Abaddon's long-feared attack was imminent came in the form of numerous sightings of drifting vessels emerging from the Warp in the sectors of Imperial space surrounding the Eye of Terror in the Segmentum Obscurus. The Astropathic station at Belisar Majoris was the first to report that they had detected a high number of Space Hulks approaching the outer reaches of the Belisar and Agripinaa Systems. The first indications were that the majority of these Hulks were uninhabited, but this turned out to be wrong. Estimates also placed these vessels converging on multiple vectors for the core planets of each Sub-sector of the Agripinaa Sector. While the sheer number of Space Hulks suddenly emerging out of the Warp at this time was rare, it was not exceptional.

In response to this alarming report, Marshal Helk, the commander-in-chief of the Imperial Guard's 2nd Army Group, ordered the deployment of additional troops aboard the 211st, 340th and 401st Naval Interdiction Squadrons, with a view to affecting boarding operations on those Hulks suspected of harbouring life. The Commissariat tripled attachment levels to these units, and all higher command ranks were informed of the possibility that these vessels might carry the taint of the Warp. The vessels of the Adeptus Astartes boarded those Hulks that they could, but their numbers were limited, as always. The Space Marines found these Hulks to be Chaos-twisted and disease-ridden nightmares, and subsequently, every such vessel encountered was destroyed with torpedoes and bombardment cannons, but for some it was already too late. In what could not have been a coincidence, outbreaks of virulent sickness erupted among many Imperial Navy starship crews within a day of a reported sighting of the dreaded Chaos starship Plagueclaw in the outer reaches of the Urthwart System by Captain Roark of the Dauntless-class Light Cruiser Duke Lurstophan. As the sickness spread throughout the region's Imperial naval forces and the number of starships fit for duty fell exponentially with the disease's progression, even more Space Hulks dropped out of the Warp, converging on vital strategic worlds.

Ships from neighbouring Sub-sectors rushed to destroy the Hulks and a small, ad hoc fleet was assembled at the vast orbital shipyards of the Dead World of Belis Corona in the sector of the same name under the command of the Imperial Navy's Admiral Quarren. The Imperial fleet surged from port and began the hunt for the Plagueclaw, though they were to encounter something far, far worse. In the shadow of the Frenerax Dust Cloud, the Imperial fleet was ambushed by a force of Chaos warships led by the Terminus Est, the flagship of the Herald of Nurgle, the Chaos Lord Typhus of the Death Guard Traitor Legion. The battle was short and bloody, with several Imperial warships crippled in the opening salvo of torpedoes, while others were overrun by vile, diseased creatures that vomited forth from the loathsome Chaos boarding craft. Admiral Quarren recovered well from his shock and rallied his forces superbly, counterattacking and fighting his way clear of the Chaos warfleet's trap. Typhus did not pursue and the majority of Quarren's fleet was able to limp back to port at Belis Corona. The Battle of Frenerax had been a costly disaster for the Imperium, but there was much worse to come. During the return journey to Belis Corona, thousands of Imperial Navy crewmen sickened and died and only with the help of system pilots was the Imperial fleet able to dock safely.

But if the situation at Belis Corona was bad, it was worse elsewhere. Many of the Plague Hulks had slipped through the Imperial defensive net and the same contagion that had struck down the Imperial starships' crews was spreading like wildfire through many inhabited worlds in the Cadian and Agripinaa Sectors as well as those of the Belis Corona Sector. The Hive World of Subiaco Diablo proved to be an ideal breeding ground for the unknown plague and was quickly quarantined by officers from the Adeptus Administratum's Officio Medicae, but not before millions of people had already sickened and died. Within a standard month, a dozen other worlds reported cases of the same plague and panic spread throughout the Segmentum Obscuras as transit between neighbouring sectors was halted by the Imperial Navy in an attempt to stop further infection.

As the epidemic spread, apocalyptic religious sects once more began to appear on every world afflicted with the disease, just as they had before the outbreak of the Gothic War, preaching that the Emperor's wrath had descended upon them and was a punishment for their sins of wickedness and vice. Only the truly faithful would be spared the Curse of Unbelief, as they named the plague, and hordes of flagellants filled the streets of every world adjacent to the Eye of Terror. The continued health of these fanatics in the face of the plague gave their words the sheen of truth and millions flocked to hear their extreme rhetoric out of fear for their lives. The plague continued to spread, but it was on Subiaco Diablo that the true horror of the disease was finally revealed. To the shock and disgust of the planet's inhabitants, the mass graves deep in the ash plains of the Hive World that contained the bodies of the afflicted heaved and split open and the corpses of those who had perished in the plague climbed up from the lime-encrusted ground. Soon millions of shambling corpses were advancing on the nearby hive city that they had once called home, clawing their way inside and attacking the already disease-weakened inhabitants.

Within months, plague zombies were climbing from their graves on scores of worlds throughout the Segmentum's Belis Corona and Agripinaa Sectors and Imperial forces were stretched to their limits in containing these Chaos abominations as well as mobs of flagellating zealots who burned medicae ward facilities to the ground in their misguided attempts to stop the spread of the plague. Paralysed by the sheer scale of the zombie epidemic, the Imperial Navy forces in these regions were completely unprepared for the vast Chaos warfleet that emerged from the Warp at the edge of the Subiaco Diablo System and surged into Imperial space. The Herald of Nurgle, the Traveller, Typhus of the Death Guard, had come to reap the harvest of his plague of undeath and there was nothing to stand in his way as he claimed the world of Subiaco Diablo as the newest province in the Plague Lord's eternal kingdom of death.

Signs and Portents
As the Zombie Plague known as the Curse of Unbelief swept through many Imperial worlds throughout the Belis Corona and Agripnaa Sectors, fanatical cults preaching that the Imperium had forsaken the teachings of the Emperor grew in number. They decried the sufferers' sickness as just punishment for their wickedness, claiming that only in the flames of purgation could the cure be found, and they would provide both. On the worlds of Malin's Reach and Lelithar, Imperial rule all but broke down as the plague crippled the authorities' ability to contain the rantings of self-proclaimed "Prophets of the End Times" who whipped entire populations into frenzies of insanity. The Ecclesiarchy had despatched the highest officers of the Imperial Church to quiet the souls of the people, yet at this time of direst need the Adeptus Ministorum had itself become embroiled in internecine conflict. A number of Cardinals had cast their lot with those who preached that the Emperor's judgment had found his servants wanting, rendering the Synods of the sectors surrounding the Eye of Terror impotent and powerless to impose their spiritual authority when it was most desperately needed. Naval facilities and symbols of Imperial rule were openly attacked and over the following weeks, mob rule virtually replaced that of the Administratum on many outlying worlds.

Overpopulated Hive Worlds as far apart as the Scarus and the Cadian Sectors erupted in violence, seemingly without cause. Even the higher echelons of Hive World Tabor and the naval base at Belis Corona proved to be riven with Chaos Cults. Charismatic demagogues incited frenzied mobs to fight the ruthless, crushing oppression inherent in the Imperium's system of rule, and hundreds of thousands heeded their seditious ravings. Assassinations and poisonings heralded new eras of anarchy in key warzones, and whole supply fleets mysteriously vanished. Nemesis Tessera, St. Josmane’s Hope and Lelithar were all ravaged by insurrection. In the panicked streets of Thracian Primaris, one man alone had succeeded in uniting the desperate citizens against the evils of Chaos as a raving prophet. The worlds of the Belis Corona System underwent a massive recruitment drive for the Imperial Guard and the Imperial Navy, and priestly delegations stirred up the new Imperial conscripts into a fever of righteous anger.

In the wake of such a catastrophic breakdown of Imperial rule on so many planets in the sectors surrounding the Eye of Terror, vast disturbances were sensed in the Warp, stirring the already volatile medium of the Empyrean into new and violent life. The fringes of Warp Storm Baphomael expanded to engulf the edges of the Cadian System and many of the Astropaths based there reported terrible visions and bloody omens that all pointed to a time of coming war. Reports kept pouring in which indicated a horrifying escalation in the scale of these disturbances. While news from across the Segmentum was sketchy at best, it appeared that a massive psychic backlash had caused the Astropathic Choir Chamber at Belisar in one of the spires of Hive Teriax to explode. The top nine levels of the spire had been obliterated and the death toll was numbered in the tens of thousands.

Any doubt that Chaos was in the ascendant was cast aside following these events on almost every civilised world. Even on Cadia the Imperium had seen signs of recidivist activity. So close to the Eye, the Cadians had come to expect the taint of the Warp to afflict those of weak soul, and they had learned to recognise and excise its influence wherever it was found. In one notable incident, Lord Commissar Salin seconded a company of Kasrkin assigned to Headquarters Security and led a raid upon the barracks of the 92nd Cadian Regiment. He rounded up a cadre of senior officers who, he claimed, were in league with agents of the Warp. No evidence of his accusation was presented to the General Staff and there was no duty upon the Lord Commissar to do so. The officers were summarily executed upon the parade ground of Kasr Orlak. That highly regarded officers of the Cadian military might have thrown in their lot with the Archenemy filled many souls with shame and confirmed the worst of their fears. A dark time was surely approaching.

The Voice of the Emperor
On the world of Lelithar, a powerful figure had arisen amongst the raving cults and fanatics, proclaiming himself to be the "Voice of the Emperor." An orator of fearsome skill, this mysterious individual had roused entire populations with his passionate speeches. Many within the Sector High Command advocated the extermination of this individual, lest his outpourings lead to further unrest. However, all across the system the backlash of those still faithful to the Imperium began. The Inquisition's Ordos Cadia, the representative of the three Ordos in the Cadian Sector, believed this so-called "Voice of the Emperor" to be an individual of the utmost danger. Lelithar was home to several thousand Planetary Defence Force regiments divided into 65 Army Groups, and it appeared that an estimated 40 percent of their personnel had thrown in their lot with the so-called "Voice." Many of these units had deserted, a large number actually making it off-world, where they had dispersed to varying locations including Yayor, Amistel, Albitern and Bar-el. That the Imperial forces had lost such a body of men to a demagogue was cause for grave concern in itself, but it was enough for the High Command that the Ordo Hereticus wanted him dead.

Within a week, there was a great resurgence of orthodox piety amongst the Imperial citizenry,as a reaction against the so-called "Voice of the Emperor." Sector High Command had initially feared that the teachings of this Heretic might plunge the region into the depths of apostasy, yet the people actually rallied against his twisted followers, casting down his prophets and decrying his false words. His days were numbered as Inquisitorial agents of the Throne hunted the elusive "Voice." Though Chaos and anarchy had come to a great many worlds of the Imperium, they still had reason for hope, for all was not lost while their faith remained strong. The great strength of the Imperium was finally stirring. Cadian High Command ordered a muster to take place at Cadia, upon the ancient and venerated Tyrok Fields, so that the Imperium could begin the Emperor's work in earnest.

Sabotage and Insurrection
Several systems in the Scarus Sector soon reported enemy activity as did three Sub-sectors located along the Cassandra Spar. Reports also came from Phonosar Prime, indicating an attack by wariors thought to be of the Night Lords Traitor Legion. The raid was timed to coincide with the local annual Festival of the Three Maidens,a holy time for the population of Phonosar Prime and its three moons, during which the adherents fasted and meditated upon their own weaknesses, the better to serve their Lord the God-Emperor. Evidently, the attackers took advantage of the fact that most of the world's population were cloistered in prayer and descended upon the capital city of Medea like a pack of feral predators upon its prey. Survivors reported that the enemy made planet fall at Medea's primary generatorium, destroying it and plunging the city into darkness before crippling the city's reserve power facilities. With the city's power grid out of action, the Traitors stalked the streets, killing wantonly as and when they saw fit. It was many hours before the Planetary Defence Forces could be mobilised to face the threat, although many militia units mounted heroic improvised counter-attacks, all to no avail. By the time the native defence forces were able to muster, the raiders had vanished into the darkness, leaving a death toll of many thousands in their wake.

The world of Xersia had also suffered at the hands of the enemy. A delegation from the Order of the Wounded Heart, an Order Militant of the Adepta Sororitas, had arrived on the world. Immediately after the Battle-Sisters' arrival, it was reported that a small force of unidentified Traitor Marines had been defeated when they came to the aid of a Chaos Cult that the Sisters were engaged upon purging. It appears the cult had chosen their moment to call upon the Traitors with great care, hoping that the counterattack would wipe out the small force of Battle-Sisters as they closed upon their target. It is a great credit to the Sororitas that they defeated both the cultists and the Renegades, and a commendation was passed on to their Canoness Superior. Sector High Command also received garbled Astropathic communications from forces in the Helotas, Sarlax, Vagera and Skyren Systems over the following twelve hours. Though no details were immediately confirmed, High Command feared the worst.

The Ormantep Raid
The listening station at Ormantep had also come under attack by Traitor forces. The attackers were a small, elite company of Black Legionaries who fell upon the listening post with cold, methodical brutality and cut down all they encountered. However, they seemed specifically determined to murder the Astropathic Choir that resided within the central keep. The unit of Cadian Kasrkin defending the station mounted a heroic defence that held off the Chaos Space Marines for several hours before aid came from a totally unanticipated quarter. It appears that the Traitors were repelled, though by a force the Imperium has no record of. As the Traitors closed on the hastily constructed barricades of the Ormantep listening station's inner sanctum, survivors reported that the night was filled with a mournful howl which sounded from all directions. As the Black Legionaries faltered in their attack and cast glances in all directions, the rearmost were dragged into the shadows. Soon, the Chaos Space Marines were firing their Bolters on full automatic and emptying entire magazines into the gloom, as more were set upon by an enemy the Kasrkin defenders could not discern. In only minutes, the Black Legionaries were all dead. Their bodies were found savagely ripped open as if by hugely powerful jaws or raked by savage claws. The only evidence of this mysterious force that attacked them was the distorted Vox-recording of the howls that filled the complex in the moments before the Chaos Space Marines attacked. It would later be determined by Imperial scholars that these mysterious "saviours" were none other than the long-lost Space Wolves 13th Great Company, lost for ten millennia within the Warp since the closing days of the Horus Heresy. Reports indicated only a handful, at most, of the station's personnel had survived the attack, and they had requested a naval task force redirect to Ormantep to ascertain what exactly had occurred. All of this came at a time when civil disorder across the surrounding sectors in the Segmentum Obscurus had reached unprecedented levels. Now the Imperial forces had to guard against both traitors within and traitors without.

Battle of Tyrok Fields
During the outset of Abaddon's 13th Black Crusade, an act of the basest treachery struck at the heart of the Imperium's defences. At the time, Cadia was alive with the diligent preparations of the servants of the Emperor. Regiments of Cadian Shock Troopers were being mustered alongside the Adeptus Mechanicus' Titan Legions and Skitarii. Regiments of mighty-thewed feral warriors stood alongside the brightly accoutred troops of the Mordian Iron Guard. Amongst this mighty throng, faith welled strong and the morale of every man soared to see the amassed power of the Emperor. But a vile serpent lay ready to strike. The regiments of the Volscani Cataphracts had landed on Cadia to join the muster at Kasr Ty'rok. Yet, in truth, the troops and officers of the Volscani regiments feared to face the Forces of Chaos again, and even if they had not formally pledged their allegiance to the Dark Gods, they had decided that it was better to die in clean battle against men in service to a dark cause than to stand at the gate to the Warp and close ranks in the face of the powers of Hell once more. As the defenders of the Cadian Gate prepared for conflict, the traitorous Volscani Cataphracts revealed their new allegiance to the Ruinous Powers when they unexpectedly struck in force at the Imperial Guard troops being mustered at the Tyrok Fields.

The Traitors slaughtered thousands of loyal Guardsmen before any response could be coordinated. The intent of the Volscani's treason was revealed as they swarmed aboard the Leviathan, Excubitoi Castellum, which served as the command vehicle of the Governor Primus Marius Porelska of Cadia. The Traitors proceeded to slaughter him and much of the senior command of Cadia's armed forces. This included the commander-in-chief of the defenders of the Cadian Gate, who was killed in the brutal attack. At the darkest moment, then-Colonel Ursarkar E. Creed took control of the dire situation. Rallying the 8th Cadian Shock Troops Regiment, the bloodied Imperial defenders were quickly organised and ordered to advance upon the Traitors. The 8th Cadian led the charge into the ranks of the Volscani. Creed and Jarran Kell, his Regimental Standard Bearer and most trusted friend, led the way during the counter-attack, and it was they who reached the command deck first and succeeded in preventing the foul desecration of the fallen body of the Governor Primus.

The Governor had fallen, as a Cadian should with a blade in his hand and Heretics at his feet. Creed carried the body of the Governor back to the battlements of the Leviathan, wrapped in the banner of the 8th Cadian. Many more Cadian regiments came upon the scene and a great throng of them gathered around. Colonel Creed, being a pious man, allowed them to sing their praise to the God-Emperor and then from his lofty position he delivered his first exhortation to the armies of Cadia, to strive without rest until every disciple of Chaos had suffered the same fate as the Volscani. The host demanded that Ursarkar should take command. Three times he refused the offer, but ultimately he acceded to the will of the massed regiments of Cadia. As ever, greatness thrust itself upon Ursarkar E. Creed and he could but strain to bear its weight. Through Creed's actions, what might have been a grievous defeat for the Imperium and a nefarious victory for the hordes of the Archenemy, was turned into a defining moment for the defenders of Cadia. Every man and woman of the Fortress World swore to repurpose themselves to the defence of the Emperor's realm.

Preparations for War
Following the betrayal on Cadia, pleas for aid from Imperial forces beyond the Cadian Sector had been despatched to military commands in the surrounding sectors. Warriors from the lauded Chapters of the Astartes Praeses and from the Space Wolves were expected to reinforce the beleaguered Imperial forces. Naval assets had been promised from Cypra Mundi and regimental muster had begun in many nearby sectors. The full might of the Imperium was gathering, but only time would tell whether or not it would arrive in time. That a major Chaos incursion was imminent was now beyond doubt, but the Archenemy would find the Imperium ready, if only the preparations could ne completed in time.

Creed promoted those Imperial Guard officers he felt were worthy and ruthlessly demoted or transferred those officers he deemed ineffectual. Though many resented his brusque manner, and he had undoubtedly made many enemies amongst the established Cadian officer class, many believed that his approach was a necessary one, considering the monumental task at hand. Though Cadian morale had been dealt a terrible blow by the betrayal at Kasr Ty'rok, Ursakar E. Creed had rallied the Imperial Guard and Planetary Defence Forces charged with the defence of Cadia and the Cadian Gate magnificently as Cadia's new commander-in-chief and Lord Castellan. Though many senior officers had seen men who had fought a hundred battles over their careers waver, a single word from Creed could galvanise them into action. The man was imbued with fierce resolution, and those under him could not help but be infected by it.

The work of organising the forces at Cadia's disposal continued at a rapid pace as the penultimate year of the 41st Millennium opened. As was standard practice, each world contributed regiments and organised its forces into battle groups, and Sector High Command assigned Departmento Munitorum support services to each as they become available. Cadia was fortunate in that many worlds of the worlds Segmentum Obscurus followed the Cadian example with regard to regimental structure, equipment and combat doctrine, though there were notable exceptions to this rule, with Imperial Guard units such as those raised from the worlds of Finreht and Mordant. With a starting establishment of six to nine Imperial Guard regiments per battle group, and at least six such groups formed into an army, Cadian Sector High Command had been able to assign a minimum of ten army groups to the defence of every notable world in the region, with the capital worlds assigned as many as one hundred. Of course, experiences showed that these battle groups would soon break down once they were required to redeploy to meet combat needs as a conflict developed, and staff officers on the ground would need to organise their forces as best they were able. Such was the reality of staff work when one was required to coordinate highly diverse units over such vast distances.

The Storm Breaks
"And lo, as the veil is drawn on the last age of Man, the Despoiler shall gather his hosts once more. Where twelve times before the Faithful have cast him out, now shall he prove their undoing. For Man has grown weak, despairing at the woes of the galaxy. Where are the Faithful now? Where are the men that stood beside our Lord the Immortal Emperor and at his side conquered all? Gone. They are less than ashes in the cold, cold earth. At the Thirteenth hour shall the Despoiler return. All Humanity shall tremble, for lo, his doom is upon him."

- The last Oration of the Heretic Archivist of the Gethsemene Reclusium

With the worlds of the Cadian Gate all but on their knees with the weight of internal strife and the outbreak of the so-called Plague of Unbelief, Abaddon the Despoiler launched an invasion into the Emperor's realm and unleashed a power beyond imagining, the scale of which had not been seen since the darkest days of the Horus Heresy.

As part of their constant vigil around the Eye of Terror, highly trained units of Cadian Kasrkin often pushed into the outer reaches of that swirling maelstrom, desperate to find some indication of where the first blow would land in early 999.M41. Astropathic divination pointed towards the blighted world of Urthwart, a world already taken by Chaos, its population enslaved and sacrificed to the Dark Gods. Finding nothing alive on Urthwart, merely death and hideous Plague Zombies infected with the Curse of Unbelief, the Karskin prepared to withdraw. Suddenly, a frantic Vox communication from the Cadians' warships in orbit reported numerous vessels advancing on Urthwart from the Eye of Terror. The Karskin attempted to fall back to their dropships to return to their troop carriers, but it was already too late. The Imperial ships in orbit were either crippled or were forced to disengage and make best speed for Cadia. There was to be no escape for the Karskin who were stranded on Urthwart as a massive vessel, larger than the most gargantuan capital ship of the Imperium, approached the doomed world: the Planet Killer. Few were aware of the existence of this monstrous ship, for it had been thought lost at the Battle of Kharlos II during the Gothic War centuries earlier. Oblivious to their fate, the stranded Cadians could do nothing as the incomprehensible power of the Planet Killer was unleashed in a devastating lance of energy that annihilated the blighted world they were trapped upon and reduced it to spinning pieces of molten rock floating in the void. As Urthwart died, collapsing in on itself, a Chaos warfleet composed of hundreds of warships and hulking troop transports surged from the depths of the Eye of Terror, heralding the beginning of Abaddon the Despoiler's fearful 13th Black Crusade. A psychic death scream, more piercing than the Astronomican itself, ripped through the ether from the doomed world of Urthwart.

Astropaths and forward Imperial listening posts detected the emergence into realspaceofaTraitor warfleet consisting of hundreds of warships and hulking troop transport vessels. All were on a course for Cadia. Reports indicated that the Plagueclaw and Terminus Est, along with a massive flotilla of Plague Hulks, had emerged in the Subiaco Diablo System. Worse than this, unconfirmed reports claimed that two Blackstone Fortresses accompanied the Chaos warfleet. Cadian Sector High Command found this last fact difficult to countenance, though given the state of the sector in the previous months, they could not discount the possibility that these ancient xenos weapons still existed within the hands of the Forces of Chaos.

Imperial naval experts began plotting worlds likely to be chosen as targets for the Planet Killer's attentions. Intelligence gathered during the Gothic War indicated that the Planet Killer was a ponderous vessel, and its planet-cracking Armageddon Gun took a great deal of time to power up and exert its effect upon a world once it was functional. The vessel was likely to be accompanied by a large fleet, which would be employed to subdue and distract the Imperium's own naval forces until the Planet Killer could unleash its main weapon. All available Imperial naval assets had therefore been tasked with locating such a flotilla, and system defence pickets were put on high alert for any signs an unusually large Chaos warfleet approaching one of their worlds.

Nemesis Tessera
The wave of Abaddon's invasion soon broke across the sectors surrounding the Cadian Gate, and it became evident that the Inquisition Fortress World of Nemesis Tessera was to be the main target of the first phase of Chaos assaults. This was first realised when the Archenemy launched an assault on the Chima Lomas System. Nereus, the primary world of the system, was taken by enemy forces with contemptuous ease. In the Cadian High Command's best reckoning Chima Lomas had not been a target in its own right, but had been taken merely to secure the Forces of Chaos' lines of communication along the Rhoke Conduit. Native defence forces, amounting to seventeen Planetary Defence Force army groups supported by the Imperial Guard's Battlegroup Neth, contested the enemy's planetfall three hundred kilometres south of the Nereus Delta. Going by the few intelligence reports on the situation they possessed, the Cadian High Command was able to determine that the valiant defenders of Nereus had held up an invasion force at least fifty times their own strength for a whole day. The last transmission the Cadian High Command received from General Neth suggested that he was prepared to sell his forces dearly.

Having crushed Chima Lomas, Abaddon's forces dispersed as they entered the Kensi Gulf, with splinter forces separating to assault the world of Ovaris Gulag, where no command communications had been received in over a month. The voyage across the Kensi Gulf to Nemesis Tessera was accomplished with alarming speed, with all elements of the Chaotic fleet translating into the target system within a week of one another -- a feat of astronavigation through the Warp that the Navis Nobilite suggested to the Cadian High Command would only be possible with the aid of the darkest of sorcerous arts. Why the enemy had chosen an Inquisitorial Fortress World like Nemesis Tessera as the initial target of its assault remained a mystery. Cadian Sector High Command's best guess was that the system was chosen out of sheer hatred for the most potent agents of the Golden Throne.

That the forces of the Archenemy regarded the destruction of Nemesis Tessera as of the utmost importance was evident from the Sector High Command's observations and from intercepted communications. The forces of the Archenemy invested an unusual amount of its resources in this assault. After the Forces of Chaos made their landings, it appeared that the Inquisition's fortress might be able to hold, yet Cadian High Command could only speculate that the icy surface of that grim world must have been infested with millions of Traitors and Heretics who had made planetfall upon it. They estimated that those who did not fall to Nemesis Tessera's inhospitable climate would soon be hunted down and exterminated by the blessed agents of the Inquisition. But soon the Segmentum High Command came to realise that the assault on Nemesis Tessera had been but a prelude to the even greater storm that was about to engulf the Cadian Sector.

Chaos Advances
"Let the galaxy burn."

- Abaddon the Despoiler, Warmaster of Chaos

Soon the skies above the worlds of the Imperium in the Segmentum Obscuras turned black with innumerable dropcraft as the dread Forces of Chaos began their invasion. The Planet Killer itself, Abaddon’s flagship, drifted ever closer to the Cadian System. Terrible, mighty Chaos Space Marines trod the surface of worlds they had not set foot upon for ten millennia and their hatred and thirst for vengeance truly knew no bounds. The Imperial Navy, for long weeks forced to fight a desperate holding action against the seemingly endless waves of Chaotic vessels, was eventually reinforced. With their orbital defences already breached and the fleet forced into withdrawal, world after world in the Cadian Sector came under attack. Initially the Imperial forces held, even throwing the enemy back at Belisar, Macharia, Vigilatum and especially Xersia and Kantrael. Yet the enemy soon found their weak points, throwing countless thousands of lowborn filth at the Imperial forces so that the Chaos armada's real masters, the Traitor Marines, could exploit them.

The Chaos warfleets continued their inexorable advance upon Cadia, only stopping to allow the Blackstone Fortresses to scour Demios Binary to a barren rock. Lightning arcs of incandescent energies razed the planet's surface bare, killing millions of Imperial servants and destroying every structure in a matter of hours. Chaos vessels quickly overwhelmed the orbital defences of Solar Mariatus, the outermost planet of the Cadian System, and hundreds of dropships carrying Traitor Guard regiments of the now-infamous Volscani Cataphracts descended to the surface, attacking the mining outposts and capturing the valuable ore refineries from the defending units of the 23rd Cadian Regiment. The Traitor forces established a forward base of operations on Solar Mariatus from which to launch attacks throughout the system.

Saint Josmane's Hope
The first of the inner worlds of the Cadian System to fall was the Prison World of Saint Josmane's Hope, whose inmates were believed to have thrown their lot in with the invaders in the vain hope of being granted freedom. They were granted only eternal damnation, for their liberators turned out to be the Renegade Space Marines of the Violators warband, devoted servants of Slaanesh, the Prince of Pleasure. Brutal, close-quarters fighting erupted all across the continent-sized prison and many of the guards kept a last bullet for themselves rather than allow themselves to be taken by the frenzied inmates. Welcoming the Traitor forces as liberators, the inmates were to be horrifyingly disabused of this notion as those allowed to live through the "pleasures" inflicted upon them by the Slaaneshi Astartes were instead taken as slaves for the Chaos warfleet or conscripted into its armies of Traitor Guard.

Many officers within Cadian High Command had not heard of the Violators until they had been invited to a closed session briefing along with Lord Castellan Creed, where a representative of the Inquisition imparted to them the awful truth concerning these hedonistic Heretics, so that Imperial forces would be better prepared to combat them. What they were told about the Violators' activities filled even hardened veterans with horror, for no man, no matter his crime, deserved to have the attentions of such vile creatures visited upon him. Soon the defences of every one of the worlds in the Cadian System were sorely tested, and despite the efforts of the Commissariat to maintain Imperial morale through censorship of news, word spread of the atrocities being committed upon Saint Josmane's Hope.

Following a week of disastrous events upon the penal world, the Lord Castellan issued an order the like of which many believed they would never be required to enact. The world of Saint Josmane's Hope was to be subjected to Exterminatus and destroyed utterly. The enaction of an Exterminatus was beyond the resources available to the Imperial forces present in the system; the agents of the Inquisition confirmed this and said that their own ships that carried the needed weapons of mass destruction were many weeks distant. Logan Grimnar, the Great Wolf (Chapter Master) of the Space Wolves, also confirmed that none of the available vessels of his Chapter fleet carried Cyclonic Torpedoes, and neither did any Astartes warship within range. The Imperial Navy put forward the plan of instigating a massive bombardment of the world using Nova Cannons, in the hope of causing a degree of tectonic instability, but all available intelligence suggested that the Chaotic fleets blockading Saint Josmane's Hope's orbital space were too strong. The bombardment vessels would not survive to launch a single shell, let alone the hundred or more required to complete the task. Finally, it was put forth by the Adeptus Mechanicus' representative that tectonic instability could be created by overloading the generatorium grid of the planet's main prison complex. The resulting explosion would pierce the world's crust, thereby causing a meltdown to "sing" through the planet's outer crust and into its mantle. This would cause the crust, followed by the planetary mantle, to tear itself apart. The only drawback to this plan was that such an objective would need to be completed by a team of operatives on the ground, for it could not be attempted remotely. A special team was assembled in short order and given the moniker "Strike Force Herald." It was composed of an unlikely mix which included Astartes from the Space Wolves, Howling Griffons, Subjugators and Iron Knights Chapters, three squads from three different Imperial Guard regiments, a Death Cult Assassin, five Tech-priests and a number of additional support personnel, in addition to an unnamed pair of Inquisitors. This small force was assembled in under an hour after the Cadian High Command approved the plane, and it immediately left for Saint Josmane's Hope. Twenty-four hours before this strike force was due to achieve its objective, the evacuation order was issued to those few forces the Imperium still commanded on the surface of Saint Josmane's Hope. The order was given after Strike Force Herald made planetfall.

Following the issue of the evacuation order, Imperial forces upon the planet began a fighting withdrawal worthy of the greatest of commanders. Never had anyone heard or read of such heroism as was displayed during the desperate rearguard actions of that day. Regiments laid down their lives so that entire armies could escape to their transports. Even as those transports departed, men stood their ground at the overrun landing areas and fought to the death rather than board the escape vessels, so determined were they that their comrades should live to fight another day. The Imperial force's plan was ultimately successful and Saint Josmane's Hope was destroyed. Unfortunately, none of the operatives of Strike Force Herald survived to return to Cadia after carrying out this desperate mission to tell the tale of their own heroics.

The Greenskin Threat
With Warp Storms rendering Astropathic communications erratic, the Segmentum Obscuras High Command continued to experience enormous difficulties coordinating command and control of its forces. Communications from the more distant sectors was particularly affected, and Imperial Commanders were advised that those communications they did receive from distant sources were not to be trusted, due to psychodynamic distortion. A particularly implausible report from the Scarus Sector indicated that in addition to Chaos attacks, the defenders there faced the menace of the Orks. After action reports cited Mordax Prime as the initial focus of a massive Ork incursion which occurred at the same time as the Chaos assault was first hitting the Segmentum, and if this were just an isolated case High Command would normally have written off the communication as misinformation caused by inexperienced troops facing an enemy they had no experience with. However, every major star system in the Scarus Sector soon logged similar reports, so they had to be taken seriously until more detailed information was forthcoming.

First Contact
On Cadia, Lord Castellan Ursarkar E. Creed led his Cadian 8th (now being referred to as "the Lord Castellan's Own") on an operation to hunt down and exterminate a group of Volscani Cataphracts who, unknown to Cadian High Command, had escaped the chaos of the Tyrok Fields and were attempting to link up with elements of Abaddon's invasion force. The Lord Castellan had always been known as an officer who would fight at the frontline with no hesitation whatsoever, leading his men and setting the standard for his junior officers. The 8th Cadian brought the enemy to battle at Kasr Vasan, in the shadow of the Cadian Pylon that dominated the Vasani Moors. The battle was brief yet vicious in intensity, and not a single Traitor was allowed to escape with his worthless life. It later proved fortunate that Creed had wasted no time whatsoever in launching his assault, for a Chaos Space Marine force, believed to be the vanguard of a larger Black Legion warband, caught up with him as dusk fell, necessitating a hasty withdrawal across the moors. It was said that the true test of a general was the ability to disengage in the face of a superior foe, and the 8th Cadian regrouped, to head back out onto the moors to face the Black Legion on more favourable terms.

Following the evacuation and subsequent destruction of Saint Josmane's Hope in order to deny the forces of the Despoiler a forward staging point, Imperium defenders initially rallied well, falling back in good order to key points in the Cadian system. Imperial morale was bolstered by a bold series of counter attacks, but these successes were to prove short-lived, and the Despoiler had committed yet more of his diabolical forces to the Cadian system. With the Forces of Disorder now fully committed to the Siege of Cadia, the beleaguered defenders could only pray help arrived soon, before all was lost.

Reinforcements
Cadian High Command eventually received word that the fleets of the Iron Knights and Imperial Fists Chapters of the Adeptus Astartes had established contact. Lord Castellan Creed was also in conference with the Great Wolf Logan Grimnar of the Space Wolves Chapter, planning how best the Space Marines might be deployed. Though the Cadian Sector High Command held no authority over the Adeptus Astartes, Creed had indicated his support for Grimnar should he establish himself as the nominal head of the Space Marine Chapters operating in the region. Captain Echion of the Patriarchs of Ulixis, commander of the Ultramarines Honour Company, a specialised company of the Ultramarines that had been stationed at the Cadian Gate for many millennia, rotating officers and warriors from Ultramarines companies elsewhere and also drawing from the Ultramarines' Successor Chapters, also voiced his support for this arrangement. Lastly, the Cadian High Command also received word from the Adeptus Mechanicus temple at Kasr Gallan that the Ordo Reductor, consisting of ancient and venerated siege engines akin to the Dreadnoughts of the Astartes, was to reinforce the Cadian defences there.

More Bad News
Unfortunately, not all the news that reached the Cadian High Command at this time was good. The situation on the world of Lelithar had taken a drastic turn for the worse. In an attempt to bring to ground the Heretic calling himself the "Voice of the Emperor," the Legio Ignatum of the Collegia Titanica, the Death Spectres Space Marine Chapter and the Jouran Dragoons Imperial Guard Regiment laid siege to that world's capital city. Soon after the arrival of these forces a large proportion of Lelithar's native defence forces and populace rebelled and took up arms against their government, slaughtering the Planetary Governor and his staff in an orgy of bloodletting. The Lelithar security forces and the Adeptus Arbites reacted with commendable speed, breaking up suspected Chaos Cults and anti-Imperial organisations, but once again, Lelithar was plunged into anarchy. It concerned the Cadian High Command greatly that they were still unable to control Lelithar. Even with the presence of a Titan Legionand a Chapter of the Adeptus Astartes on the world, the rebels continued their actions and the "Voice of the Emperor" continued broadcasting his lies across the region.

Many within the Cadian High Command continued to labour on an analysis of the Traitor Legions' attacks. This task was ordered directly by the Lord Castellan, and had brought about a degree of conflict within the High Command, for Commander Azrael of the Dark Angels Chapter heard of this endeavour and ordered it to cease, stating that the actions of the Traitors were the business of the Astartes themselves, and were of no concern to mortal units. Creed rejected this assertion as patently ridiculous under the circumstances of the current crisis, and Logan Grimnar agreed with him. As a result, Azrael soon withdrew what cooperation the Dark Angels had been prepared to offer.

Chaos Vanguard
Multiple incidents of new Chaos incursions continued to be logged with the Cadian High Command, the greatest number of which involved the Night Lords Traitor Legion. Imperial analysts had reached the conclusion that this Legion had been employed in a vanguard role throughout the early stages of the Chaos invasion and it had been extremely effective in its mission. The Night Lords were notorious for the cruelty of their assaults, as their predilection for inflicting wanton cruelty on all they encountered was well-known across the Imperium. The Archenemy was believed to have utilised the Night Lords in this role in order to foment panic in Imperial civilian populations as a result of the brutality of these attacks. The people of many worlds were consumed by panic that their planet would be the next to suffer at the hands of the Night Lords.

While the Night Lords had been deployed to serve as terror troops, the insidious Astartes of the Alpha Legion were employed by Abaddon as infiltrators. This particular force was one that the officers of the Cadian High Command had been briefed on by the Ordo Malleus, who considered their activities of dire import. Reports of scattered enemy attacks upon key Imperial facilities had been continuously received by the Cadian High Command, but these minor attacks had seemed to pale in significance when compared to the overall scale of the Chaos invasion. However, closer analysis along with the information received from the Inquisition lead the Imperial forces to believe that these attacks actually represented the work of the Alpha Legion. Further investigations revealed that a number of rear echelon supply and communication facilities were amongst the targets hit. One could not help but wonder whether these objectives were designed to hinder the movements of Imperial reinforcements into the region from further afield.

The Emperor's Children, led by the immortal favoured Chaos Champion of Slaanesh, Lucius the Eternal, feasted well upon the agony of the population of the world of Belisar. The Plague Marines of the Death Guard stalked across the battlefields of the planet Amistel, the ground beneath their feet cluttered with the unquiet corpses of those who the Plague of Unbelief had consumed. In the wake of these Traitor Legions come the hordes of the Lost and the Damned: Traitor Guard, mutants, Chaos Cultists and human fiends of the very worst aspect who despoiled the domains of Mankind by their very presence. The acts of wanton destruction and desecration they proceeded to carry out in the name of the Ruinous Powers shook even the most stoic defenders of the Imperium to the core.

War in the Void
While the war continued to go badly upon the surface of many worlds in the Cadian System, in particular Saint Josmane's Hope and Solar Mariatus, the war in space was fought more on the Imperium's terms. The Cadian System had been the focus of the Abaddon's primary fleet actions, and the Imperium's fortunes there changed from day to day. The situation was highly fluid and the Chaotic naval forces found themselves stretched to exploit the victories they had won. Although the Imperial Navy's fleets could not hope to oppose those of the Archenemy in and around the orbital space of most of the worlds of the Cadian System, they continued to hold on to control of the inter-system space lanes within the Cadian Sector. The Imperium could not under any circumstances afford to let their guard waver, for it was upon one of these routes that they hoped to bring the Planet Killer to battle. To let it past was too terrible a failure to contemplate.

A fleet the size of which has not been seen since the end of the Gothic War eight standard centuries earlier had been dispatched from Cypra Mundi, and arrived at Belis Corona in preparation for a massive Imperial counter-offensive into the Cadian Gate. The arrival of this vast armada allowed those Imperial vessels that had been fighting continuously since the beginning of the invasion a brief respite. Severely depleted ship’s companies were bolstered through indiscriminate press-ganging, and hasty repairs and refits were undertaken on those vessels most in need of them.

The Imperial reinforcements were split into battlegroups, each tasked with bolstering the defences in a specific sector of the Segmentum Obscurus. The regions around the Eye of Terror encompass many millions of cubic light years, and only by the concentrated application of resources in those areas in most desperate need could the Imperial Navy hope to make inroads and slow, stall, and eventually repel the Chaos warfleets plaguing the region. During the latter stages of the campaign, when Abaddon's fleet was seen approaching the Agri-World of Lortox, the Ultramarines Honour Company distinguished itself with a bold, spaceborne counter-assault against Abaddon's fleet as the Planet Killer closed with that Imperial world on the outskirts of the Agripinaa Sector. The action bought Lortox's Planetary Defence Forces time to evacuate a significant proportion of the population before the world was destroyed by Abaddon's horrific weapon of planetary destruction. The Ultramarines Honour Company managed to succeed in crippling the Planet Killer, but the massive vessel still had enough power to limp away. In the aftermath of the Lortox Evacuations, the Ultramarines Honour Company redeployed to Cadia and the surrounding star systems, launching a series of operations to hinder Abaddon's forces as they assaulted the Imperial positions. These attacks included a series of highly successful boarding actions against the lumbering Space Hulks being used to transport vast hordes of the Archenemy's troops to reinforce Abaddon's siege of Cadia.

It was a fool's dream to hope the Planet Killer could be found before it was brought to bear upon the Imperial forces. Without warning, it appeared in orbit over the world of Macharia. Though many could scarcely believe it, the world was destroyed by the massive vessel. It was lost, and with it millions of loyal and faithful subjects of the Emperor, dead at the hands of the Despoiler and his despicable weapon. Utter dread now descended upon the Segmentum Obscurus High Command. Despite the successes of the early weeks of the invasion, many had come to believe that this war might not be won in the short term. Where at first the Imperial forces fought to repulse Abaddon's assault, to deny him footholds upon Imperial worlds, they now fought to keep him from overwhelming them entirely. This was a grim paradigm, and one the Imperial forces were not ready to accept. They believed Abaddon dare not destroy Cadia, as its Pylons were reckoned intrinsic to the continued stability of the Cadian Gate which he needed to move his forces deeper into Imperial space so that he could launch an assault upon Terra. So the Imperium would make its last stand upon Cadia and hold that world, no matter the cost.

Enemy of My Enemy
With every world in the Sectors Oculus (sectors surrounding the Eye of Terror) now embroiled in a war that had already claimed countless billions of lives, a new and unexpected faction suddenly took a hand in events. The ever-elusive ships of the Eldar had been sighted by the crews of many Imperial Navy vessels, and by troopers on the ground, across at least a dozen sectors. In the depths of interstellar space, these xenos warships reportedly intervened in battles between the Imperial Navy and the Chaos invaders, on occasion providing aid to Imperial warships and allowed them time to escape when overwhelmed, but at other times attacking them without provocation. The Dark Eldar had also been sighted, preying on the lesser worlds of the Cadian Sector and they had even taken slaves on the Feral World of Medusa, the homeworld of the Iron Hands Chapter. It was even rumoured that a legendary Eldar faction referred to by the Ordo Xenos as Harlequins had been sighted on the battlefields of Agripinaa and Scelus.

The Eldar had also been sighted upon the worlds of the Cadian Gate as well. Cadian High Command had long been aware that the Eldar of the Ulthwé Craftworld maintained a strong presence in the vicinity of the Eye of Terror. Though little was known of their ways, it was widely believed that they ultimately worked torwards the downfall of the Archenemy. Indeed, the Black Guardians of Ulthwé had taken a hand in a number of battles, appearing unexpectedly and without any warning upon the surface of planets though distant from any Eldar activity. Upon Belis Corona, Eldar strike forces had freed Imperial Navy ground crews from the Chaos legions closing in on them. However, there were also reports from the Cadian System of the Eldar falling upon themselves in fits of madness, from the Agripinaa Sector of the Eldar attacking the warriors of the Ultramarines Honour Company, and that their ghost-ships harboured fiendish beasts of the Warp. As ever with these mercurial xenos, their motivations proved as           alien as they were unpredictable.

An Ancient Foe
"Their number is legion, their name is death."

- Eldrad Ulthran, Farseer of Craftworld Ulthwé

The Ordo Xenos also informed the Cadian High Command of yet another threat from an unexpected quarter, the return of the ancient and implacable xenos known as the Necrons who had been found to be active in the Sentinel Worlds. These soulless automatons were suspected to have laid dormant in some manner upon the Sentinel Worlds for many years, perhaps for millennia. Though they had slumbered right underneath the Imperium's noses, somehow they had awoken, most likely in reaction to the activities of Abaddon and the Forces of Chaos. In some manner the Necrons were known to be the very antithesis of the Warp, stirred into activity by its waxing power. The Necrons' nature compelled them to oppose the Warp in all its forms, and for all intents and purposes, this adversarial posture could be considered in human terms an utter loathing for Chaos.

Chaos represented the greatest peril for the Imperium, yet Mankind paradoxically relied on the Warp for interstellar travel, communication and much more. The Necrons, however, received no such benefits from the Warp. They had no psykers to draw upon the Immaterium, while their advanced technology provided them with power over the material universe that rivalled the abilities of the strongest psykers. In practical terms, this meant that the Imperium could expect the newly awakened xenos to oppose the Forces of Chaos. However, this did not mean that the Imperial forces could or should treat them as allies, even in the loosest sense, for this ancient race was anathema to Humanity -- they were death incarnate to the entire species, who the Necron Lords viewed as primitive interlopers within the rightful territory of their ancient empire. Lord Castellan Creed immediately enacted orders for all Imperial forces to stay clear of this xenos race, and to allow them to engage the Forces of Chaos wherever and whenever it was their intention to do so. However, the Imperial forces were not, under any circumstances, to render aid to these xenos, for to do so would be to the ultimate harm of Mankind. The Imperium would tolerate the Necrons' presence in Imperial space only so long as expedience dictated. These ancient undying xenos might be the enemy of humanity's enemy, but that did not make them the Imperium's friend.

For the Greater Good
With the Imperium committing more and more resources towards the defence of the Cadian Gate after 997.M41, reports from the Eastern Fringe of the Ultima Segmentum suggested the Tau Empire was using this time when the Imperium's eyes were elsewhere to strengthen its defences, and even enlarge its own domain in what the Tau called the Third Sphere Expansion. Though the xenos had yet to threaten Imperial worlds at this time, and were largely expanding into uncontested Wilderness Space, Imperial Stategos keep one wary eye on the Tau Empire, lest they use this time of conflict and uncertainty to their own advantage, to the eternal cost of the Imperium.

The Imperium's commanders were right to be worried. In 999.M41, the Tau initiated a major military campaign to seize Imperial territory in the Eastern Fringe that would coincide with the 13th Black Crusade and become known as the Zeist Campaign. As the Imperium's military was heavily involved with preventing the breakout of the Forces of Chaos from the Cadian Gate on the other side of Imperial space, the Tau took advantage of this distraction to rapidly expand their territory. The Imperium responded with the dispatch of several units drawn from the Chapters of the Adeptus Astartes to the Zeist Sector to blunt the Tau offensive. With the victory of the Astartes in destroying the last major Tau forward logistical base in the sector at the world of Augura, the Zeist Campaign marked the end of the Third Sphere Expansion, with the Tau Empire having grown to 133% of its prior size. Unfortunately for the Imperium, though the Space Marines had won the war and stopped the Tau's seizure of human territory, it was not possible to sanction a retaliatory thrust into Tau-held space as the individual Space Marine forces were required elsewhere in the galaxy to hold the line against the Forces of Chaos during the height of the 13th Black Crusade.

Enemies Everywhere
The Cadian High Command was also briefed by the Ordo Xenos on a number of other factions which assailed Mankind as the Forces of Chaos battered at the doors of the Cadian Gate. The Eldar are once again active in and around the Sectors Oculus. Inquisitorial forces attempted to ascertain their intentions, for their actions appeared contrary and mercurial -- one moment actively aiding Imperial forces, the next slaughtering them. The Cadian High Command held no illusions that the Eldar fought for anyone other than themselves, and proceeded to plan accordingly. The Orks appeared to be increasingly active in the Scarus Sector. The Ordo Xenos believed the Greenskins there had been building up for an invasion for some time, lurking in the unexplored depths of Wilderness Space and launching their attack with a low cunning few would expect of such barbarous creatures. Lastly, the Inquisition warned the Cadian High Command to be alert for seemingly incongruous reports of alien infiltrations in the region near the Subiaco Diablo System, particularly for attacks coming up from below the galactic plane. They would not expound further on what they meant by this, but insisted that the Cadian High Command should inform the Inquisition immediately should any such attacks by unknown xenos materialise. Despite being beset on all sides, the Imperial forces and their commanders remained imbued with a sense of righteous indignation. If every damned creature in the galaxy was now ranged against them, then they were determined to take them all into oblivion with the last cry of the human race.

Thasia
Within the Malin's Reach System, a new and even more dire threat had arisen. The Dark Apostle Erebus and his forces from the Word Bearers Traitor Legion were causing great damage to Imperial efforts to defend the region. This enemy was of a particularly insidious nature, as the self-styled prophet of the Ruinous Powers sought to convert the people of the Imperium as much as to slaughter them. Spreading his foul corruption far and wide, he had managed to manipulate the Ultramarines Honour Company into an attack upon the world of Thasia, the fourth planet in the Malin's Reach System. The company hoped to draw Erebus to battle in the dark, methane shrouded groves of the planet's surface, but found that the Dark Apostle had instead drawn them into a trap. The Word Bearers were far from Thasia by the time the Ultramarines arrived, who instead found a force of Eldar waiting for them at the site of one of those xenos' planet-bound Webway transit portals through the Warp. Upon making plane fall, Captain Echion, the leader of the Honour Company, ordered his force to make ready for battle, but not to launch an assault upon the xenos immediately. He had been advised by the Cadian High Command that the Eldar had on occasion aided Imperial forces, and though he knew well the duplicity of these xenos, he nonetheless afforded them the opportuniry to retire without the need for bloodshed.

Unfortunately, the malicious xenos were of a mind for war, and launched an unprovoked attack upon Echion's forces. The battle that ensued was a prolonged and vicious one, with running combats being fought through the dark, vitrified forests. Death would come by stealth for both sides, and both sustained terrible levels of casualties. In time, Echion ordered his diminished force to regroup at its drop-zone for one last assault upon the duplicitous foe, but in doing so, found the enemy's positions abandoned. Upon coming to the Eldar portal, Echion's Librarian, Lesrus of the Sons of Guilliman, advised him that the xenos had fled through their Webway, and were working to seal the portal from afar. Echion washed his hands of the Eldar, determined never to give them the benefit of the doubt again, due to the loss of so many of his brethren for such little gain. So it transpired that Erebus had not only skillfully maneuvered two of his foes into wasting precious time in futile combat against each other, but he had made use of the distraction to launch an attack elsewhere, upon the primary world of the Malin's Reach System.

Malin's Reach
The world of Malin's Reach was subjected to hell over a period of three days and three nights. Warp Storms flared into being around the planet, shrouding its three moons behind a sickly violet haze, quickly followed by waking nightmares which wracked the population. Many took their own lives, so terrible were their visions of insanity made real, and many more roamed the streets enacting wanton acts of carnage and madness upon each other. On the third night the Word Bearers' landing craft streaked from the tortured sky, securing a drop-zone scant kilometres from the Ministorum District of the world's capital of Ruskin City. The defenders of Malin's Reach could only offer scant resistance to the Traitor Marines' assault as they were debilitated by the ordeal of many hours of psychic torture. The Word Bearers fell on Ruskin Cathedral committing such blasphemies that by Imperial edict, all loyal servants of the Emperor were forbidden to recount them, save for high-ranked individuals. Through some unknown means the Word Bearers were able to summon forth the creatures of the Warp into the ruined cathedral, before returning to their dropcraft and departing. The Imperial forces on Malin's Reach were sorely pressed for many days containing the daemonic incursion, and the creatures unleashed there were only banished when Captain Echion's forces arrived in orbit and obliterated the entire site with an orbital bombardment. It was, the commander of the Ultramarines Honour Company recounted, the only way to be sure. Though a great many of the Imperium's forces present on the world were lost in the barrage, along with the greater part of the capital city, it was considered a merciful end for the them. Such a slaughter was the terrible price of protecting the Emperor's domains from the remorseless daemonic servants of the Ruinous Powers.

War in the Webway
The Eldar Webway, the secret Labyrinthine Realm of the Eldar race through which the length of the galaxy can be traversed in but a single step, was penetrated during the 13th Black Crusade by intruders bent on nothing less than the theft of its most dreadful secrets. Ahriman, amongst the greatest of Chaos Sorcerers and the former Chief Librarian of the Thousand Sons Traitor Legion, had somehow gained access to the Webway. For millennia, this practitioner of the darkest of arts had sought this prize, and he intended to fathom the route through the Webway to the Black Library, the hidden Craftworld that was the repository of all the knowledge gained by the Eldar race over millions of Terran years on the subject of Chaos.

The Black Library was a "dark" Craftworld that eternally travelled through the infinite corridors of the Webway. Its location and route through the Webway were numbered among the greatest secrets of the Eldar races, and were hidden from all but the Harlequins and the members of the Black Council, the governing body of the Black Library within the Labyrinthine Dimension. Like all Craftworlds, the vessel was both sentient and psychoactive, hiding itself from all psychic probes, while simultaneously repelling Warp entities and other physical intrusions. The Black Library is an enormous construct with a scorched, crystalline appearance, covered in vanes and flourishes but with the typical flowing grace of Eldar architecture. The interior is an intentional maze comprised of all manner of convoluted passages, corridors, and chambers. Bubble vaults full of stasis caskets containing forbidden lore and dangerous artefacts, hang from the superstructure, whilst inside and above are myriad citadels, obelisks, monoliths, and spires where the rest of the Craftworld's arcane contents are kept.

Such was the desperation of the situation that these guardians took an active role in the defence of their realm, for the Webway itself twisted and split like a live thing wherever Ahriman and his followers tread. Rumours of Warp-beasts the size of Battleships bolstering Ahriman’s forces had implications too terrifying to contemplate. In response to Ahriman’s intrusion, the Eldar launched a massive counter-attack, the force of which belied their woefully low numbers. The activities of the Ulthwé Strike Forces increased beyond measure, and a desperate running battle was fought across the Webway and upon the surfaces of those worlds that harboured entrances to it. As a consequence, worlds within the Eye of Terror itself were fought over, as previously sealed entrances to the Webway were unsealed in the battle for dominance. Eidolon and Belial IV were two such worlds, Crone Worlds long ago lost to the Eldar race at the Fall of their empire ten millennia past, and now vital to the survival of their race. It was rumoured that one of the immortal Phoenix Lords, none other than Maugan-Ra, the Harvester of Souls, lead the Eldar forces across the Crone Worlds of the Belial System, and that ancient Eldar artefacts were unearthed by the forces of the Archenemy.

Defence of Ex Lucan VII
With the number of attacks by Eldar raiders increasing alarmingly, the Adeptus Astartes' command council deployed a number of Astartes forces tasked with the specific objective of challenging them. It appeared that these raids were actually being conducted by the Dark Eldar, the twisted kin of the xenos that resided on the Craftworlds, and though the Imperial forces held the entire Eldar race in due contempt, it was this faction which they decided to target in an effort to teach them the lesson that the might of the Imperium, although slow to react, was impossible to avoid forever. Aid finally came from an unexpected quarter for the the beleaguered forces of the Imperium in the form of the Dark Angels Chapter of the Adeptus Astartes/ The Dark Angels, who had so pursued their own mysterious ends throughout the conflict, had finally extended their full cooperation in the effort. Acting upon intelligence passed to the Cadian High Command by the Ordo Xenos, and relayed to the Dark Angels by Commander Azrael, four entire companies of the Chapter, and three of a number of its Successor Chapters, collectively known as "Taskforce Shadowguard", staged upon the outlying Cadian Sector Mining World of Ex Lucan VII. There, the Astartes taskforce lay in wait within the hollow mountains of the Kyran Range, every vehicle powered down, in order to ambush a sizable Dark Eldar raiding force. Appearing out of nowhere through the Webway portals the Dark Eldar made extensive use of, the sadistic xenos wasted no time in launching their attack against the mining settlements of the Kyran Range. Taskforce Shadowguard revealed themselves and took the first raider force completely by surprise. Exploiting the momentum of victory, Taskforce Shadowguard executed a manoeuvre that smashed aside a second xenos force. Unable to coordinate their assault in order to create a breakthrough in the Astartes' lines, the Dark Eldar raiders were annihilated in a devastating massacre. The result was an outstanding victory for the forces of the Imperium that taught the deviant xenos a lesson that they would not soon forget.

Xersia
The Imperial campaign against the Dark Eldar, though nothing more than a distraction from the maelstrom of the Despoiler's invasion, soon posted another victory. Another force of Dark Eldar raiders had been defeated, on this occasion by the Relictors Space Marine Chapter, upon the world of Xersia. The Relictors had not formally acknowledged the command authority of Logan Grimnar's Adeptus Astartes command council, and appeared to have launched this attack upon their own initiative, not as a response to command council directives. It was believed by the Cadian High Command that the Dark Eldar's raids simply attracted the Chapter's attentions, and the raiders paid for their crimes in blood.

Xersia was a well-garrisoned star system, and many of the Imperial forces present there witnessed the Relictors' assault. It was said that the Chapter slaughtered three entire Kabals, purging the system and hunting down every last xenos before slaying them without mercy. The Chapter's officers were said to bear arms of terrifying potency: swords able to spew cleansing flame, and axes that sucked the essence of the Emperor's foes from their bodies, leaving nothing behind but a dried husk. The Chapter marched under arcane banners and icons of tangible power, the followers of their enemies scattering before them. The Relictors delivered the Emperor's wrath wherever they passed. A number of Imperial Guard officers on the ground at Xersia attempted to contact the Relictors' Chapter Master, Commander Artekus Bardane, but the Chapter Master refused to acknowledge their communications.

Subsequent to this action, the Relictors appeared in a number of other campaigns before arriving in the Cadia System. The Chapter was known to have participated in an attack against a warband of the Word Bearers Traitor Legion on the world of Subiaco Diablo, during which an Inquisitorial task force disappeared under suspicious circumstances. They were next seen in the Cadian Sector, where they clashed with a Night Lords force at Exeltra Minor, before becoming embroiled in the suppression action against the Dark Eldar raiders at Xersia. The Chapter next appeared near Cadia itself. Upon their arrival in-system, the Great Wolf Logan Grimnar issued orders that the Chapter should reinforce the Imperial garrisons of Cadia. Commander Bardane refused to acknowledge Grimnar's orders, and his fleet departed the system, headed, by best estimates, for the Agri-World of Fremas. Grimnar was furious that the Relictors had refused to submit to his command. In a fit of rage, Grimnar ordered his most elite Wolf Scouts to track down the Relictors and discover the true nature of their mission.

Exactly what occurred at Fremas is a matter of some doubt, but the Pack of Wolf Scouts dispatched by Logan Grimnar tracked the Relictors to the remote Diamedes Archive, where the Chapter appeared to have repulsed a Chaos attack before turning upon the Archive's defenders. None of the defenders were reported to have survived the assault, but Grimnar's men recovered partial video-logs that suggest the Relictors' objective was the sealed stasis vault at the heart of the mountain top fastness. The contents of this vault were known to but a handful of Adepts in the Imperium, most of whom resided on Terra. The Relictors' actions would later put them in conflict with both the Inquisition and later, the High Lords of Terra, which put the future of their Chapter in dire jeopardy.

Preparations and Counteroffensive
For long weeks the Imperial Navy had been forced to fight a desperate holding action against the seemingly endless waves of Chaos vessels, but its battlefleets had finally been reinforced. An Imperial fleet the size of which has not been seen since the end of the Gothic War eight standard centuries earlier had been dispatched from Cypra Mundi, and staged itself at Belis Corona in preparation for a massive counter-offensive into the Cadian Gate. The arrival of this vast armada allowed those Imperial vessels that had been fighting continuously since the beginning of the invasion a brief respite. Severely depleted ship’s companies were bolstered through indiscriminate press-ganging, and hasty repairs and refits were undertaken on those vessels most in need of them.

The Imperial reinforcements were split into battlegroups, each tasked with bolstering the Imperial defences in a specific sector of the Segmentum Obscurus. The regions around the Eye of Terror encompassed many millions of cubic light years, and only by the concentrated application of resources in those areas in most desperate need could the Imperial Navy hope to make inroads and slow, stall, and eventually repel the Chaos warfleets plaguing the region. If the Imperial Nary could somehow gain the upper hand in the conflict, it was hoped the enemy would soon find their forces cut off from aid and reinforcement. Although Ork mercenaries had reportedly joined the fray and the fleets of the Eldar had mysteriously been drawn away from the Cadian Gate for unknown reasons, the iron fist of the Imperium was slowly but deliberately being brought to bear. Ancient defence laser batteries upon Demios Binary combined with programs of orbital bombardment on Laurentix and Sewan to harass the servants of Chaos wherever they were to be found.

Lord Admiral Quarren, the commander of Imperial Navy assets in the Cadian System, had succeeded time and time again in defeating Chaos warfleets many times the size of his own, allowing reinforcements to enter the fray around the Fortress Worlds of the Cadian System. At the same time, a massive influx of reinforcements in the Scelus System of the Cadian Sector had penetrated the Chaos blockade of ships and minefields, and in the Belis Corona System of the Belis Corona Sector the entirety of Battlefleet Gothic had stormed into the fray. Infernal mines sewn across the battlefront accounted for the destruction of only a few vessels in the fleet, and now Battlefleet Gothic had the opportunity to avenge the losses it had suffered in the Gothic War at the hands of Abaddon the Despoiler's own warfleet. If the relentless momentum of the invasion could be slowed for just a short time, then the defenders on the ground would have a real chance of victory. The Imperial Navy had gambled all on this sector-wide retaliation and should it fail, than Battlefleet Obscurus would be so weakened that only the redeployment of fleets across the whole Imperium would hold any hope of holding back the Despoiler's invasion.

Vermaard Assault
Lord Castellan Ursarkar E. Creed soon ordered the redeployment of Imperial troops defending the Feral World of Scelus to bolster the defences there. Scelus was firmly under Imperial control following the defensive efforts of Lord Marshall Attica and a number of Astartes forces. The problem had been the blockade which the Archenemy's warfleets had placed around Scelus itself, in order to prevent Imperial forces from redeploying. To expedite the breakout, there was a planned push upon the enemy forces located near the Mining World of Vermaard. The Cadian Sector High Command hoped that vessels of the Chaotic blockade fleet would be drawn off to oppose it. Simultaneously, a battle group upon the surface of Vermaard would launch a sudden frontal assault upon enemy positions, with the intention that the Chaotic blockade fleet would be forced to ferry ground troops from Scelus to Vermaard, thus complicating their departure. This ruse ultimately proved successful, too successful, and it reminded Imperial commanders that the reactions of the servants of the Ruinous Powers could never be fully anticipated.

The Vermaard Assault was a complete success in that it caught the enemy unawares. It appeared that the hordes of Chaos Cultists forming the Chaos presence upon Vermaard were engaged in some form of mass ritual, the culmination of which was disrupted by the Imperial forces' attack. The cultists were caught unprepared to defend their positions and were cut down with negligible losses to the Imperium's own forces. As anticipated, the enemy began to move troops upon the surface of Scelus up to orbit, and their warfleets waited for the troops transfer to be completed before setting off to relieve Vermaard.

At this point, Lord Marshall Attica made his breakout from Scelus, leading 40 percent of his force to their own transport ships and running the gauntlet of the remainder of the Chaotic blockade fleet. Though a number of his troop transport ships did not make it through the enemy lines, a great many did; enough, in fact, to render that portion of the operation a success. Indeed, the Imperial Navy could not possibly have hoped that such a great number of Chaos vessels would be pulled out of the line, for had more remained, Attica's breakout would have been far less of a success than it proved.

However, three days later, the Archenemy's reinforcements reached Vermaard. So great were the number of Chaotic troops ferried there that the Imperial forces stood next to no chance against them. History may never fully recount the sacrifices made at Vermaard so that Attica's force could reach Cadia. It appeared the Imperial forces had stirred up a veritable hornet's nest by interrupting the mass ritual there, but Imperial commanders could not help but wonder what evil might have transpired had they not acted.

Eldar
The activities of the Craftworld Eldar against the Forces of Chaos had ceased unexpectedly at this point in the conflict. For weeks the starships of the Eldar had been active across the Cadian Sector, in most instances striking against the assets of the Archenemy, though on occasion they had also attacked Imperial forces for no discernable reason. Now, it was as if they had simply disappeared. Entire staffs of Imperial savants, seers and Strategos had been assigned the task of tracing the activities and objectives of the Eldar, and were in constant communication with the Ordo Xenos in this regard. Long-range scouts had caught brief glimpses of movement, but as the Cadian High Command had already learned, when the Eldar wished to remain hidden, there was little even their most skilled crews could do to find them.

Progress was eventually made in determining the reason for the sudden disappearance of the Eldar fleets when an Imperial scout vessel managed to record traces of Eldar activity in System XT90304/G, an empty star system in Wilderness Space thirty light years to the galactic northeast of Belis Corona. On the outskirts of the system, the Imperial vessel picked up readings of a vessel of prodigious size, and managed to execute a single pict-capture before being detected. The pict-capture confirmed just why the Eldar had redirected their efforts. The forces of Abaddon were in possession of a Blackstone Fortress, an ancient xenos-forged engine of destruction not seen since the end of the Gothic War. As if the presence of the Planet Killerin the Sectors Oculus of the Segmentum Obscurus were not dire enough a threat, now the Imperium had to contend with this new threat. If the notoriously aloof and uncaring Eldar were prepared to throw the majority of their forces into combating the Blackstone Fortresses, the threat they represented must have been terrible indeed.

Orks
The Orks continued putting intolerable pressure on a number of worlds in the Scarus Sector, notably Lethe II and Mordax Prime. The Magi Biologus of the Adeptus Mechanicus believed these foul creatures to be working alongside Abaddon the Despoiler to further their own ends, though they did not consider it to be a true alliance as such. More likely the Orks were taking advantage of the opportunity provided by the Despoiler's invasion to launch new attacks against distracted Imperial targets.

The situation on these worlds was grim indeed. In particular, Mordax Prime could not be allowed to fall into Greenskin hands, for it was a Forge World of prodigious output and its loss would damage the Imperium's war effort. More to the point, the Imperial forces dreaded the monstrosities the Orks might turn the production lines of Mordax Prime to creating. Fifteen Imperial Guard Army Groups and 5 legions of cybernetic Mechanicus Skitarii troops continued to hold Mordax Prime, yet clearly such a large body of men was insufficient to stem the green tide engulfing that Forge World. The Segmentum Obscurus High Command drew up plans to send a further 35 to 40 regiments of the Imperial Guard to the world, drawn from the regional reserve to help bolster Mordax Prime's defences. Yet the Orks had set their sights upon capturing Mordax Prime, broadcasting their designs for the planet they referred to as "MoreDakka Prime" on every Imperial channel. Were it not for the fact that Mordax Prime was the sovereign preserve of the Adeptus Mechanicus, Imperial High Command seriously considered petitioning the Inquisition for an Exterminatus against the world before its vast resources fell to the enemy.

Tides of War
By this point in the conflict, on every world of the Cadian System, there was only war. Vigilatum was all but lost to the unholy servants of the Ruinous Powers, though a small Imperial rearguard, previously thought annihilated, held out, stubbornly defending the Naval Tac Logis facility. Solar Mariatus, too, was sorely pressed by the hordes of the Despoiler, and the Cadian Sector High Command had ordered the world reinforced, lest its output of munitions and other materiel essential to the ongoing war effort be lost -- a blow the beleaguered Imperial defenders could ill afford. With Imperial Navy reinforcements inbound, the defenders of Cadia had to hold out just a little while longer.

Ursarkar Creed had been hailed by many as the most able Imperial Guard commander since the legendary Lord Solar Macharius, yet many Imperial observers noted that his sub-commanders had not proved themselves quite so capable. So sudden and mobile had the Abaddon's invasion proved that many Imperial Commanders at the star system and planetary level had simply been unable to coordinate their actions, and were reacting to the enemy's attacks rather than dictating their own terms of battle. Creed had issued stern orders to his subordinates to take the initiative at a planetary level or fall to the enemy, for the choice was that simple.

Though the Archenemy had gained temporary advantage over Imperial forces at Vermaard, the Imperium was now firmly in control of Scelus. A number of cross-substantiated Astropathic communications confirmed that the situation on that Feral World was positive. Creed ordered a further 20 Imperial Guard regiments from Scelus to be made ready for transit to other Cadian Sector warzones, an order that would be executed if and when the Warp Storms scarring the sector abated. But after long days of silence from across the Cadian Sector, a single message managed to penetrate the ether. The Scarus Sector fared ill, and its Imperial defenders begged that the Cadian High Command dispatch reinforcements with all haste. Only the industrial Hive World of Thracian Primaris stood before the tide of the Ork menace and the Chaos filth assaulting the sector, and with each passing day another world in the Scarus Sector slipped further from the Imperium's grasp. It appeared that Belis Corona was suffering at the hands of the Archenemy, and even the Imperial Navy was having a difficult time of it in this region.

Elsewhere, the Imperial Navy's Battlegroup Eclipse managed to halt the predations of an inbound Dark Eldar fleet. Despite being severely outmatched, the Imperial Navy's vessels managed to cause catastrophic damage on the weakling ships of the Dark Eldar, many brave crewmen giving their lives in the process. These xenos evidently employed some manner of cloaking device, for at first the Battlegroup believed them to be a previously unknown Chaos warfleet. That they were able to defeat this attack was cause for great celebration, but the Imperial Navy knew it had to increase its vigilance tenfold against further such incursions.

Fall of Ibrium
Abaddon soon unleashed a new and calamitous phase in his invasion. One of his allies, the infamous iconoclast and blasphemer Erebus, the Dark Apostle of the Word Bearers Traitor Legion, had unleashed the foulest of forbidden sorceries upon the loyal subjects of the God-Emperor of Mankind. Upon the world of Ibrium, a Shrine World of the Ecclesiarchy, the Dark Apostle had ordered the building of immense cathedrals' dedicated to the Dark Powers of the Warp. That these monstrosities existed upon such a formerly sacred world was a profanity beyond words, but, according to Imperial intelligence reports, they were constructed at the expense of a million souls; souls promised to the Emperor. Upon the completion of these dark monuments, Erebus ordered the ritual execution of every last innocent who still drew breath on the planet at the completion of their labours. The Dark Apostle's sins did not end at genocide. The rites by which the peoples of Ibrium were sacrificed drew forth the full fury of the Empyrean, unleashing its anger upon the domains of Mankind. Seething Warp Storms that threatened to cut the Cadian System off entirely from the outside wracked Imperial space lanes, and the Eye of Terror throbbed with malevolent purpose.

The raw stuff of the Warp had been unleashed, pouring through the rents in the thin skein of reality created by the Word Bearers' incantations, and calling up vast Warp Storms across the region. Many outlying worlds of the segmentum, such as Scelus and Caliban, were now engulfed in raging tempests, some simply cut off from aid, others reduced to shifting realms of madness as the denizens of the Empyrean ran riot across entire worlds. Ibrium was amongst the worst-affected worlds: where once proud Ecclesiarchy Cathedrals had stood, now blasphemous monuments to the powers of the Warp proclaimed the dominion of Chaos. Across the Cadian Sector, where kilometre-high Hive Cities had once pieced the clouds, now gargantuan charnel houses dominated worlds forever lost to Mankind.

Soon Astropathic communications from vessels caught in the flaring of the Eye of Terror and at least three Warp Storms in the immediate region lead the Cadian High Command to conclude that Erebus intended to isolate the Imperial forces by making Warp-travel all but impossible. To a certain degree, Erebus had succeeded, though the Imperial forces were still able to remain in contact with the majority of their commands by way of Astropathic relay. The Warp Storms continued to grow more intense with each passing day, and the Cadian Sector High Command's command and control capability was stretched to the limit. Contact was lost with entire worlds, armies and fleets, and unfortunately the High Command was forced to rely upon increasingly compromised Astropathic communications for each scrap of information that could be garnered about the overall situation.

The Betrayer
Despite the interference from the Warp, Astropathic reports continued to trickle in to the Cadian High Command. The most disturbing of these was a transmission from a Planetary Defence Force major upon the world of Tabor, whose brutal accounts of the events afflicting his garrison made for gruesome reading. If the report was to be believed, none other than Khârn of the World Eaters Traitor Legion, the so-called "Betrayer," had fallen upon that doomed world and shed the blood of its brave defenders in the name of his unspeakable patron Khorne the Blood God. Despite the arrival of this fiend, Imperial forces had made gains upon Tabor and across the Agripinaa Sector. If the Imperial defenders could somehow contain Khârn's mad rampage, the strategic situation in that region would be, at the very least, somewhat more acceptable.

Pursuit of the Voice
During the campaigns of the 13th Black Crusade, the Dark Angels' and Space Wolves' ancient mutual rivalry caused severe disruptions to Imperial defensive efforts in the Sentinel Worlds area. Though both forces operated in the same region for several weeks, they refused to coordinate their actions, harming the ability of the Imperial Guard commanders on the ground to act, for they could not rely upon the aid of either Chapter. The situation soon changed, as the Dark Angels abruptly left the area in search of renegade individuals they refused to identify. The Dark Angels sought the shadowy Heretic calling himself the "Voice of the Emperor," who was operating on the world of Lelithar. The Dark Angels launched a number of strikes against this figure, but on each occasion found that the pressures of constant attacks upon their hallowed ground in the Caliban System forced them to redeploy their forces. Each time the Dark Angels manage to close on the suspected location of the Voice, he somehow proved able to slip through their clutches, leaving behind taunting, heretical graffiti. The Voice transmitted a number of all-channel Vox-casts throughout the war, making obscure references to the I Legion's earliest history, as well as making astonishing claims against their Primarch Lion El'Jonson. The Dark Angels and their Unforgiven Successor Chapters vehemently rebutted these blasphemous broadcasts. The Dark Angels and the Chapters of the Unforgiven relentlessly pursued this Heretic and his followers and eventually captured him. But as the Voice lay languishing within the holds of one of their vessels, he somehow, through some as yet unidentified means, managed to effect his escape.

The Green Kroosade
With the Forces of Chaos overwhelming every Imperial world within the vicinity of the Eye of Terror, a large force of Orks took advantage of the state of anarchy threatening many star systems, and launched an all-out attack upon the worlds of the Scarus Sector. This so-called "Green Kroosade" was remarkably well-coordinated for an Ork invasion, and soon succeeded in grinding down the defences of several Imperial worlds, notably Lethe XI. The Black Templars Chapter diverted a number of Fighting Companies to oppose them, lest they gather into a fully-fledged WAAAGH!

Battle of Kasr Holn
The Forces of Chaos continued to hit Imperial forces hard across the entire region surrounding the Eye of Terror. The Cadian city of Kasr Holn had borne the brunt of the Chaotic ground assault on Cadia over a number of days, with wave after wave of frenzied mutants assaulting the walls of the Fortress World's capital city. Fifteen regiments of Cadian Shock Troops manned the defences there, and an entire Legion of the Adeptus Titanicus was deployed. Were it only the seemingly endless hordes of ill-disciplined mutants attacking the capital, the Imperial defenders might have been able to contain them there, but the assaults were led by none other than the Traitor Astartes of the Black Legion. The Black Legionaries were content to allow the thousands of mutants to crash against the Cadian captial's defences, in order to wear down and deplete their materiel stores through sheer attrition. Each wave had been repulsed, but only at the cost of many brave defenders, and with little or no affect on the Archenemy force's numbers. Just when the attackers were sent once more into an undisciplined rout, the Black Legionaries were launched their own attack. These attacks cost the Imperial defenders dear, though fortunately they were unable to pierce the defenders' lines. Yet with each successive wave they were only able to kill a handful of the enemy, while the casualties the defenders sustained were intolerably high.

Lord Castellan Ursarkar E. Creed moved his headquarters to Kasr Holn to counter the crisis rapidly developing there, believing that his inspiring presence would make the same difference as the addition of several regiments. He led a bold counter-attack at the head of the Cadian 8th, "the Lord Castellan's Own," against the Forces of Chaos, sallying forth with the Imperial forces once the latest wave of mutants had receded, and struck at the Black Legion before the Chaps Space Marines' own assault could develop. This Imperial counter-attack was a resounding success, and as Creed returned to the walls of Kasr Holn at the head of the 8th Cadian, the entire length of the eastern wall erupted with the cheers of many thousands of men. But soon the Battle of Kasr Holn took on a new and unanticipated turn, one that could be scarcely believed had it not been witnessed personally.

At the height of the next assault of the mutants upon the eastern wall of the Kasr Holn's primary fortress, at the moment when it appeared as if the Black Legion would force a breach, the feral 13th Great Company of Space Wolves appeared from behind the Traitors' lines and inflicted a crushing defeat upon them. Both the Chaos attackers and the Imperial defenders heard with their own ears the animalistic howls emitted by these barbarous warriors, even though many were at their station some distance from the fighting. The sound chilled everyone that heard it to the core. Fortunately, the affect upon the enemy was greater still. The vile mutants fled first, turning their backs and fleeing in an instant. Their Black Legion masters attempted to forestall the rout, firing upon the mutants in an effort to render them more terrified of their own masters' retribution than they were of the 13th Company. But their efforts were wasted, and many Black Legionaries were trampled as the mutants stampeded from the walls. Soon, the Black Legionaries were themselves assaulted, and those not cut down from the rear were forced to quit the field, an event unheard of to date for the fierce Chaos Space Marines of Abaddon's own Traitor Legion. The 13th Company's attack was over almost as soon as it had begun, and they soon withdrew, making no attempt to communicate with the other Imperial forces as they did so.

Imperium Resurgent
With so many sectors of the Segmentum Obscurus now cut-off from Imperial reinforcement by the actions of the Forces of Chaos, the war had escalated by a degree of magnitude in those areas still accessible to both sides. The fighting in such regions as the Cadian, Scarus and Agripinaa Sectors had reached an unprecedented level, with millions throwing themselves upon the crucible of utter and total war to save the Cadian Gate from falling irrecoverably into the clutches of the Ruinous Powers. In an amazing twist of fate, the Imperial reinforcements from Battlefleet Solar arrived many weeks earlier than expected, for the tides of the Warp have never been predictable. The Lost 13th Company of the Space Wolves added their feral might to the battle for the Chaos-infested capital of Kasr Holn, and the mighty vessel Duke Lurstophan, at the head of the Imperial Navy's Battlegroup Roark, braved the Warp Storms to bring aid to the besieged Cadia. Under the bruised and crackling skies of his homeworld, Ursakar E. Creed, the Lord Castellan of Cadia, had launched a major counterassault against the Forces of Chaos infesting the Fortress World while the White Scars Chapter engaged the troops of the Archenemy across the Cadian Sector. Not a single man was spared, and the death tolls spiraled ever upward.

Space Marine Crusade
After many long weeks of beleaguered, stubborn resistance, the defenders of the Cadian Gate were finally reinforced by the combined forces of dozens of Space Marine Chapters. This Imperial Crusade had been gathered from the most distant regions of the galaxy, answering the call-to-arms issued when the forces of Abaddon had first commenced their invasion. The Space Marine Crusade was greeted with adulation and joy by the battered and bloody defenders of the Cadian Gate. Those Space Marines who had fought at the Gate since the beginning of the conflict were now joined by their brethren, and all stood ready to take the fight to the Archenemy with the courage and conviction that only the Space Marines could display.

The simmering rivalries between the Space Wolves and the Dark Angels stationed in the Sentinel Worlds were eclipsed by the alleged Fallen Angel sighting near the ruins of Caliban, and the rumours of an artefact of the Primarch Leman Russ that was held on the world of Nemesis Tessera. The Blood Angels, after their arrival at Kasr Partox on Cadia, prepared for the assault of the largest horde of World Eaters seen in living memory. Typhus, the Herald of Nurgle, took a personal hand in the battle for the world of Macharia, teleporting in and slaughtering platoon after platoon of Cadians before returning to his flagship. His gift of fear infected the Cadians' ranks even quicker than the plagues he spread by his mere presence.

Having re-established contact with the other Chapter Masters fighting in the region, Logan Grimnar, the commander of the Adeptus Astartes' command council for the campaign, dictated that all Astartes efforts should be focussed on the defence of the Cadian, Belis Corona and Agripinaa Sectors of the segmentum. Now that contact had been made with those Chapters newly arrived in the segmentum, a coordinated attack could be launched that was set to sweep away the invaders in one fell swoop. Many within the Cadian High Command prayed that two of the greatest Astartes Chapters to serve the Imperium, the Dark Angels and the Space Wolves, would set aside their internecine disagreements for long enough for their efforts to bear fruit.

With so many Space Marines now bolstering the Imperial defence, the forces of the Traitor Legions had not been idle. The Chaos rearguard joined the fray, engaging the Space Marines in every theatre of the war. Those Traitors who had turned upon their master and their kin ten millennia past were consumed with hatred for their erstwhile Battle-Brothers, and threw themselves at the new arrivals with wanton bloodlust. With such legendary warriors as the Blood Angels, the Black Templars, the Imperial Fists, the Howling Griffons, the White Scars and many more now defending Imperial space from Abaddon’s invasion, the Imperium at long last possessed a real chance to successfully turn back the 13th Black Crusade.

Agripinaa
Four companies of the Blood Angels answered the call to defend the Cadian Gate, arriving towards the middle of the conflict. A significant force of Blood Angels immediately fell upon the Chaos hordes assaulting the world of Agripinaa, and they sought out the leader of the attacking forces, the notorious Chaos Champion of Khorne Kossolax the Foresworn and his World Eaters warband, the Foresworn. In an epic confrontation likened to the mythic conflict between the Blood Angels' Primarch Sanguinius and the mighty Bloodthirster Ka'bandha at the closing of the Ultimate Gate during the height of the Horus Heresy at the Battle of Terra, the Blood Angels took the fight directly to the enemy.

Kossolax, fully aware that his bodyguard was no match for the frenzied Sons of Sanguinius, called upon the slavering daemons of Khorne for aid. The summoning rite was an act of wanton, traitorous carnage, as the warlord ordered his World Eaters to sacrifice the lives of their Chaos Cultist allies in order to gain the favour of the Blood God. Uncounted thousands were slaughtered in mere hours, their blood flowing in rivers through the corridors of Agripinaa's primary Hive City, and cascading from ventilation grills as waterfalls of gore. The sacrifice had the desired result, and as the first of the Blood Angels' veteran Assault Squads screamed into battle, a blasphemous avatar of the Blood God, another Bloodthirster, ripped its way through the skein of reality to confront the Sons of Sanguinius.

The first Blood Angels to meet the Greater Daemon were torn limb from limb, the beast devouring their sundered bodies as a taunt to their Battle-Brothers. The remaining Space Marines were sent into paroxysms of rage at such desecration, and threw themselves at the daemon with no thought for their own safety. At the height of the battle, the Sanguinary High Priest Numitor confronted the daemon, and dealt it a blow that stunned it for a brief moment. Seizing the advantage, the brothers of the Death Company leapt upon its back, but the daemon recovered, and severed the High Priest's arm with a crack of its long whip. The priest was holding one of the sacred Chapter relics known as a Blood Chalice, which bore an infinitesimal amount of the blood of the Chapter's Primarch, and the blessed liquid was spilled across the tarnished paving.

At that moment, a deathly still overcame the scene, as the Blood Angels were momentarily shocked beyond action at the sight of their Primarch's sacred blood seeping into the ground. Then, the silence was broken, as Numitor staggered to his feet and bellowed the words of the Rite of Exsanguination. The assembled brethren of the Death Company were overcome with visions of the last time their Primarch's blood had been spilt by a servant of Chaos, when Sanguinius had fallen at the hands of the Arch-Traitor Horus.

The Death Company went berserk. They hacked down the Bloodthirster in a savage, rage-fuelled frenzy, oblivious to the fact that it dragged half their number down with it, before turning their hatred upon the warband of Kossolax the Foresworn. The World Eaters were expelled from Agripinaa at great cost to the Blood Angels, though the annals of the Chapter's history will celebrate the casting out of the Greater Daemon. The Chaos Champion Kossolax was not found at the hive city, and the Sanguinary High Priest Numitor vowed to hunt him down, no matter the cost.

Amistel Majoris
Seven of the eight companies dispatched by the Howling Griffons became engaged in a gruelling trench-war on Amistel Majoris. Having broken through the Death Guard Plague Fleet blockading the world, the 2nd to 8th Companies arrived in time to bolster the regiments of the Imperial Guard's Drookian Fen Guard, who were suffering horrific losses to the hell-spawned epidemics unleashed by the Traitor Forces arrayed against them. Within days, the Howling Griffons and the Legio Astorum's Titans were the only force able to man the extensive defences constructed by the Drookians. Any warrior caught in the open and not protected by Power Armour when the plague winds hit were ensured an excruciating death, and an eternity of servitude as a Plague Zombie in Nurgle's legions of undead.

The 1st Company of the Howling Griffons, including Chapter Master Alvaro, were at the time based on the Chapter Battle Barge Force of Destiny, and were engaged in the persecution of a particularly vicious company of Night Lords Chaos Space Marines known as the Chosen, commanded by the infamous Daemon Prince Periclitor. It was widely known that the Howling Griffons harboured a particularly deep hatred of this Daemon Prince. While that hatred served the greater needs of the Imperium's defence against the Forces of Chaos, no other authority sought to question Alvaro's actions.

The Iron Knights Chapter had been engaged upon a self-imposed penitent Crusade for a number of decades when Abaddon's 13th Black Crusade smashed into the defenders of the Cadian Gate, and they were amongst the first of the Chapters in the region to respond. The Chapter's elite 1st Company soon became mired in the defence of Amistel Majoris, bolstering the flagging defences of the Howling Griffons Chapter as they fought a gruelling trench war against the unremitting assaults of the Plague Marines of the Death Guard Traitor Legion. The warzone soon became a plague-ridden quagmire, the decomposing bodies of the Plague God's victims forming putrid, sucking swamps through which the defenders were forced to wade in order to bring battle to their foes.

A sickly patina of filth soon marred the Iron Knights' gleaming blue-grey armour, and the company's Chaplains were forced to perform daily rites of purification in order to keep the virulent plague at bay. Recent sermons by these Chaplains had linked the Chapter's continuing presence in the warzone with their eventual redemption in the eyes of the Emperor, vowing that the world would only fall at the cost of the entire Chapter. By the third week of the Black Crusade, Amistel Majoris was considered sufficiently secure that a portion of its Space Marine defenders could be spared to reinforce the Cadian System, which, in the days following the destruction of Saint Josmane's Hope, was in desperate need of reinforcement.

Bellis Corona
Upon arriving at the Cadian Gate, the Doom Eagles Chapter dispatched forces to a number of warzones, notably areas that had already suffered terribly at the hands of the Forces of Chaos. The largest of these detachments, under the command of Captain Luctus of the 3rd Company, was involved in operations within the Belis Corona Sub-sector of the Belis Corona Sector, where the notoriously pious Chapter battled those who had fallen to the Curse of Unbelief. Only those without the strength of faith to resist were afflicted by the Zombie Plague, and it has been noted that not a single Doom Eagles Battle-Brother was affected by its blight. The Doom Eagles proved effective in combating the Plague Zombies infesting many worlds of the sub-sector, though, typically for this aloof Chapter, they had refused all offers of support in consolidating these successes.

Adeptus Astartes Reinforcements
A number of other Space Marine Chapters contributed to the overall defence of the Cadian Gate during the 13th Black Crusade. These Chapters included:
 * Harbingers - Although they had most recently been purging Orks from the Piscinan Belt the Harbingers Chapter had an old score to settle with the Death Guard. The Chapters' enmity towards these Traitors could be traced back to a raid on their homeworld of Birmingham, "the Black Planet," by the Death Guard, aided by the infamous Renegade known as Fabius Bile. Their Chapter Master, Nimrod Grudge, received early word of the outbreak of the Plague of Unbelief and mobilised the Chapter accordingly. Leaving most of the Chapter either in the Piscina System or on the Black Planet, the Harbingers' 1st, 4th, 7th and 9th Companies boarded their Battle Barge, Unrelenting Fury, and set course for the world of Nemesis Tessera. Immediately upon their arrival they were recruited for a special mission. As the Harbingers were known for their skill in the art of boarding Space Hulks and launching planetary assaults, it could only be assumed that their mission involved the use of that particular skill set.
 * Marines Exemplar - Led by their Chapter Master, Commander Maxim Absolon, the Marines Exemplar committed all but a single Reserve Company to the defence of the Cadian Gate early in the conflict, arriving less than a week after the Space Wolves Chapter. Accepting Logan Grimnar as the more experienced commander, Absolon allowed his companies to be deployed according to the Great Wolf's strategy, which saw them dispatched across all the warzones of the segmentum to bolster those Imperial defences most in danger of falling. Tragically, Absolon was lost in the opening phase of the conflict, as his company attempted to extract the senior staff of an Astropathic way station before the forces of Abaddon overwhelmed the jungle moon on which it was located. The 5th Columnus Regiment, a Traitor Guard unit led by the demagogue Colonel Jobe, was making a push towards the Belis Corona System, but had first to secure the jungle moon. Greatly outnumbered, Absolon led his force in a desperate breakout, and although the majority of his company escaped, the commander's Thunderhawk gunship was shot down, exploding as it failed to clear the jungle canopy. The commander was listed as missing in action, though the Marines Exemplar did not give up hope that he might have survived the crash and was still active behind enemy lines. However, Absolon's second-in-command and successor, Captain Raoul, distanced the Chapter from Logan Grimnar's Adeptus Astartes command council, preferring instead to deploy the companies of his Chapter as his own advisors saw fit.
 * Sons of Dorn - The Sons of Dorn Chapter deployed the bulk of their Chapter in the defence of the Imperium from the predations of Abbadon the Despoiler's 13th Black Crusade. They valiantly defended the same worlds along the Eye of Terror that their Chapter's legendary hero, Alexandros the Great, had liberated millennia earlier. More than half the Chapter was involved.
 * Subjugators - The Subjugators Chapter dispatched three companies directly to Cadia within days of receiving word that the Despoiler had returned, vowing that the remainder of the Chapter's resources would be mustered as soon as was possible. The Chapter arrived aboard two mighty Battle-Barges just as the Chaos warfleet was commencing its initial invasion of the Cadia System. The Subjugators threw themselves straight into the conflict, during which the 3rd Company distinguished itself by triggering the reactor overload that destroyed one of the Ramilies-class Starforts orbiting Cadia, at the very moment the Forces of Chaos gained control over it. Only a handful of the 3rd Company escaped the subsequent explosion, but their heroic sacrifice undoubtedly saved the lives of many thousands of Imperial defenders on the surface of Cadia, who would otherwise have found themselves facing the might of the starfort's guns. yet the Subjugators were reducted to a state of disarray after losing the majority of the 3rd Company in this manner. The 1st and 5th Companies took heavy casualties during the Siege of Cadia itself, notably in the defence of Kasr Gallan and the subsequent rearguard actions during the desperate Tarn Retreat, and were in serious need of resupply. The Subjugators were a recently Founded Chapter, and as such, maintained only small reserves of gene-seed. The loss of the 168 Battle-Brothers who fell on Cadia was a terrible blow to the Chapter, particularly as the Subjugators' Apothecaries were in most cases unable to recover the gene-seed of the fallen. The Chapter was eventually faced with the choice of whether to retire from the conflict and regroup, allowing time to rebuild their numbers, or to fight on regardless, and risk the death of the Chapter through sheer attrition, before it had even had a real chance to make its mark in the annals of the Imperium.
 * White Scars - The first contingent of White Scars to reach the Cadian Gate was the Brotherhood of Khajog Khan, a leader known for his victories during the Third War for Armageddon and a dozen other campaigns. Khajog led his force against the Chaos hordes massing on Cadia, launching a series of devastating hit-and-run attacks across that world's bleak moors. Within a short period of time Khajog's Brotherhood had become a major threat to Abaddon's plans, striking deep within enemy-held territory. So effective were their actions that the sieges of Kasrs Myrak, Soliq and Rantik were lifted as Chaos forces were diverted to hunt down and confront the elusive White Scars. It would seem that Khajog's attacks were in fact too effective, for Abaddon himself ordered the Brotherhood hunted down and destroyed once and for all. He knew that the White Scars planned on diverting his forces piecemeal to oppose them, but he reasoned that a full-scale response would be beyond the scope of the small Loyalist force to face. Ordering the 1st Company of the Black Legion, as well as uncounted hordes of mutants, Traitors and Chaos Cultists out onto the moors, the Despoiler began his hunt. It was through the divinations of Abaddon's most senior advisor, the Chaos Sorcerer Zaraphiston, that Khajog was finally located. Unaware that his force was being watched through Zaraphiston's scrying, Khajog launched a raid against an enemy slave train west of Lake Terror, only to discover that the convoy contained not Imperial prisoners, but the Chosen of Abaddon. The first wave of White Scars bikers hit the convoy, only to find themselves hurtling headlong into the guns of the Black Legion. The four Bike Squads, realising they stood little chance against such a foe, continued their charge nonetheless, determined to buy time for the other warriors of the Brotherhood to regroup. The warriors of the first wave sold their lives dearly, and Khajog reluctantly ordered his men to withdraw, vowing that he would return at a time of his own choosing to avenge the deaths of his Battle-Brothers. But Khajog did not get to choose the manner of his next confrontation with the enemy, for as his Brotherhood sped across the moors they found every route cut off by the Forces of Chaos. At length, Khajog decided that to flee in the face of the enemy was an insult to the honour of his Chapter, and resolved to make a last stand at the base of a Pylon on the shores of the Caducades Sea. With the Pylon to their backs and the massed hordes of Chaos to their fore, the warriors of Khajog's Brotherhood chose to defend themselves according to the ancient traditions of their homeworld by launching a suicidal charge against the enemy. The 60 White Scars smashed into a horde at least fifty times their own number, Khajog Khan at their head bellowing the battlecry of his Chapter. As the Brotherhood smashed through the ranks of the horde, its warriors were torn from their saddles, one by one falling to the sheer weight of numbers arrayed against them. Khajog rode his own Attack Bike through a sea of mutated bodies, clawed arms and whiplash tentacles seeking to drag him under with every metre he gained. Khajog Khan was the last of his Brotherhood to fall that day, and the Storm Seers of the White Scars claim that his shade remains upon the windswept moors of Cadia, unwilling and unable to return to the Chapter's homeworld of Chogoris until vengeance is visited upon the heads of those who slew him.

Lortox Evacuations
When Abaddon's fleet was seen approaching the Agri-World of Lortox, the Ultramarines Honour Company distinguished itself with a bold, spaceborne counter-assault against Abaddon's fleet as the Planet Killer closed with that Imperial world on the outskirts of the Agripinaa Sector. The action bought Lortox's Planetary Defence Forces time to evacuate a significant proportion of the population before the world was destroyed by the Despoiler's horrific weapon of planetary destruction. The Ultramarines Honour Company managed to succeed in crippling the Planet Killer, but the massive warship still had enough power to limp away. In the aftermath of the Lortox Evacuations, the Honour Company redeployed to Cadia and the surrounding star systems, launching a series of operations to hinder Abaddon's forces as they assaulted the Imperial positions. These attacks included a series of highly successful boarding actions against the lumbering Space Hulks being used to transport vast hordes of enemy troops to reinforce Abaddon's siege of Cadia.

Thracian Primaris
Upon their arrival in the Segmentum Obscurus, the Black Templars Chapter's first action was the relief of Thracian Primaris, which had sustained heavy assaults by the Forces of Chaos for some weeks. The bulk of the force consisted of Brethren previously embarked upon the hunt for Ghazghkull Mag Uruk Thraka, the infamous Ork Warlord who had unleashed such devastation upon the Imperial Hive World of Armageddon, and their participation in the action on Thracian Primaris left the pursuing Black Templars Crusades severely understrength. The Black Templars scattered the poorly led and deployed Chaos warfleet in short order, breaking through the blockade to make an uncontested planetfall at the Departmento Munitorum Logistical Support Centre at Hive Demeter. The Brethren were welcomed as liberators by the beleaguered populace, but chose not to remain on the Hive World for long, moving on to drive the Forces of Chaos across the Scarus Sector back towards the Eye of Terror.

Battle of Medusa
When the forces of Abaddon the Despoiler spilled forth from the Cadian Gate in 999.M41 to launch his 13th Black Crusade, the Iron Hands Space Marine Chapter knew that their homeworld of Medusa faced imminent invasion due to their close proximity to the Eye of Terror, and so the Chapter scrambled to prepare their defences. Given that Medusa was the only world from which the lron Hands recruited new brethren, they were forced to defend it above all other considerations. While it is known that two of the Chapter's Clan Companies were deployed elsewhere in the defence of the region, the greater strength of the Chapter was used in the defence of their homeworld.

The largest battle in the defence of Medusa came when all 10 of the gargantuan tracked fortresses of the Iron Hands' Clan Companies faced the invading Traitor Guardsmen of the Haradni 13th Heavy Armoured Regiment. The geologically unstable plains of Medusa played host to one of the largest armoured clashes the galaxy has seen since the infamous Battle of Tallarn during the Horus Heresy, when over 10,000 Traitor tanks stormed towards the waiting Iron Hands fortresses. The ensuing battle raged for five days and five nights, as the Traitors closed within firing range of the Iron Hands' mobile fortresses. When the Iron Hands opened fire, it is said that over a hundred tanks were destroyed in the first volley, for each Clan Company commanded firepower equal to a Centurio Ordinatus of the Adeptus Mechanicus.

On the fifth day, at the height of the battle, the Traitors broke through the Iron Hands' lines, and an armoured company of Traitors outflanked one of the Chapter's mobile fortresses and fired shell after shell into it at nearly point blank range. The Iron Hands responded by launching a furious counter-attack spearheaded by Assault Squads armed with Melta Bombs who leapt from the crenelated towers of the mobile fortress to land atop the enemy tanks. Though many Astartes lost their lives in the attack, shot down by pintle-mounted weapons or ground beneath the enemy vehicles' armoured tracks, their counter-attack was successful in disabling or destroying the majority of the Traitor armour and sending the rest into a disorderly retreat. It was then that the Iron Hands launched an armoured assault of their own, as whole formations of Predator Annihilator tanks disgorged from the mobile fortresses to run down and destroy the Heretic tanks with ravening beams of Lascannon fire. The Iron Hands managed to secure Medusa by the midpoint of the larger 13th Black Crusade campaign and were able to deploy several Clan Companies to the defence of the Cadian System and an Iron Hands naval task force was dispatched to reinforce the naval world of Vigilatum.

Battle of Kasr Tyrok
The Dark Angels and the Space Wolves appeared to set aside their ancient vendetta long enough for Supreme Grand Master Azrael and the Great Wolf Logan Grimnar to come to a mutual, but temporary, understanding. The two Chapters took to the field together, intent upon proving to the Archenemy that the combined forces of the Space Wolves and the Dark Angels Chapters were far greater than the sum of their parts. The exact circumstances and details of this arrangement have been kept from all who were not members of either Chapter. Both Chapters took to the field together in the defence of Kasr Tyrok upon the world of Cadia against a substantial force of Chaos mutants. The combined force of Dark Angels and Space Wolves smashed into the rear of the mutant mob, cutting them down without mercy, and each Chapter's Astartes sought to outdo the other in their skill at arms. As the last few mutants were dispatched, the Chapter's friendly banter soon turned less comradely, and insults filled the air. Victory had been achieved, but the Sons of the Lion and the Sons of Russ soon parted ways, their long-time rivalry rearing its ugly head once again.

Battle of Kasr Vasan
The lauded Imperial Fists Chapter arrived at the Cadian Gate as part of the massive Adeptus Astartes reinforcement of the region, five companies smashing into the forces of the Archenemy besieging Cadia as soon as contact was made. After an initial space engagement that saw the Chapter's Battle Barges and Strike Cruisers take a fearsome toll on the Chaos warfleet in the Cadian System, three of the companies carried out a combat drop on Cadia itself, while the other two dispersed to bolster the defences in surrounding sectors, including reinforcing the Iron Hands Chapter at their homeworld of Medusa.

The 1st, 2nd and elements of the 3rd Companies were instrumental in the defence of key points on Cadia, manning the walls of a number of fortresses with the steadfast resolution for which they are famed throughout the Imperium. In these actions, the 2nd Company was noted for exceptional acts of gallantry, overcoming a horde of mutants from the notorious Stigmatus Covenant numbering almost 10,000 heretical fanatics. At the height of the Chaos assault on the walls of Kasr Vasan, the company commander, Captain Tialo, gave his life holding a breach in the fortifications, repelling a mob of mutants numbering several hundred before succumbing to the terrible wounds inflicted upon him. The Captain's body refused to die, however, and was held in stasis by the Chapter's Techmarines, who hoped to inter it within the mighty form of a Dreadnought so that the renowned warrior might continue to battle the forces of darkness beyond the death of his mortal body.

Battle of Kasr Gehr
"Let me make one thing clear, gentlemen. We are now in the fight of our lives. The Archenemy has come to our home, with greater force and fury than ever before. All that stands between him and victory is us. Us, gentlemen. It is we who must stand before the enemy and turn him back. Why? Because we're here and there's no one else to do it for us. So if any man here believes he cannot do his duty to the Emperor, then he should present himself before the regimental commissars and stop wasting my time."

- Lord Castellan Ursarkar E. Creed, addressing the Cadian commands during the Defense of Cadia

The skies above warzones burned with the falling of orbital ordnance, and the chants of a billion lunatics resounded. The tread of mighty battle Titans shook the earth, and Imperial Navy fighter craft screamed overhead. The last days of the conflict had come upon the Imperium of Man. The Imperial forces could only pray that no servant of the Emperor faltered in his duties to the Master of Mankind, for to do so was to surrender Humanity itself on the eternal pyre of damnation and ruin. The final stage of the 13th Black Crusade was fought across the Cadian, Agripinaa, Belis Corona, Scarus and Chinchare Sectors of the Segmentum Obscurus.

On Cadia, the strongholds of the Emperor fell one by one. The Viklas and Cadus lines of battle buckled beneath the relentless hammering of uncounted enemy troops. The Imperial forces on Cadia had been engaged upon a mobile defence, with Lord Castellan Creed marshalling the Imperial Guard regiments under his command to meet each enemy and cut it off before an unstoppable assault developed. But such were the numbers of the Archenemy's forces that this strategy quickly proved to be increasingly untenable, forcing the Cadian defenders onto the defensive, as they began to fall back to Kasr Partox. An entire Traitor Titan Legion marched in line across the horizon, framed against the blazing sky as millions of tons of ordnance fell from orbit. Hordes of mutants swarmed under the Titan's feet, sacrificing themselves to the twisted god-machines. Living artillery stalked the battlefield, spewing shells the size of tanks. The chanting of a million madmen could be heard from the ramparts of Kasr Gehr.

But the Cadian 8th Regiment stood arrayed in companies across Kasr Gehr's parade ground; proud, courageous and resolute, honour writ large upon the faces of each and every trooper. The Lord Castellan knew he was consigning many within his beloved regiment to their inevitable deaths. Furthermore, the troopers knew it, and were proud to know it. They cared not, for they would uphold the pride of the "Lord Castellan's Own", Cadia and their sacred duty to the God-Emperor. That evening, the enemy launched their assault upon the citadel. It was presaged by a terrible, chilling wailing that bit deep into each man's sanity, but none wavered. Then a thunderous artillery barrage rained death and destruction upon the walls, but still the 8th Cadian refused to falter. Then came the first waves, and the men and women of the 8th Cadian opened fire upon them. A blazing wall of lasfire sprang across the rapidly closing gap before the walls, and the enemy fell by the thousands. Many exhausted their lasguns' charges in what seemed mere moments, and reached for a second charge when the regimental standard bearer, Jarran Kell, bellowed the Castellan's orders for every second company to stand down from the walls. The rearguard would assemble, and so the retreat of the Imperial forces towards Kasr Partox began.

Some ten companies had held to the last to allow the remainder of the 8th Cadian time to fall back. These brave 3,000 troops were to abandon their positions at the last possible moment, but something went wrong. They were encircled, cut off and eventually overrun and captured. A day later, the Imperial forces learned of the fate of the men captured at Kasr Gehr. They were ritually disembowelled before the Imperial positions on the Viklas line. The effect upon Imperial morale was utterly devastating, and it was all the Commissars could do to contain the air of defeat that soon settled over many units.

Death of Macharia
It was a fool's dream to hope the Planet Killer could be found before it was brought to bear upon the Imperial forces. Without warning, it appeared in orbit over the world of Macharia. Though many could scarcely believe it, the world was destroyed by the massive vessel. It was lost, and with it millions of the Emperor's loyal and faithful subjects, dead at the hands of Abaddon the Despoiler and his most fearsome and despicable weapon. Utter dread now descended upon the Cadian High Command. Despite the many successes won by Imperial forces, many Cadian officers had come to believe that the war might not be won in the short term. Where at first the Imperial forces had fought to repulse the assault of the Despoiler, to deny Abaddon footholds upon their worlds, they now fought to keep the Forces of Chaos from simply overwhelming them entirely. This was a grim paradigm, and one the Imperial forces were not ready to accept. They believed Abaddon dare not destroy Cadia using his Planet Killer or the Blackstone Fortresses, as the Fortress World's ancient xenos-built Pylons were reckoned intrinsic to the continued stability of the Cadian Gate's passage out of the Eye of Terror and deeper into Imperial space. So the Imperium's defenders decided that they would stand and hold at Cadia, no matter the cost.

Uneasy Alliance
Cadian High Command soon received word of a Blackstone Fortress approaching the Cadia System. The leader of the Eldar of the Ulthwé Craftworld, the ancient Farseer Eldrad Ulthran, contacted Ursarkar E. Creed, the overall commander of the Imperial forces. He explained to Creed that he had formulated a plan. The Lord Castellan agreed to meet him upon the Cadian plains before Kasr Partox. With his available senior staff and a cabal of Sanctioned Psykers to provide a limited defence against the powerful witcheries of the Eldar, Creed agreed to meet the Farseer. The xenos appeared before the humans through a Webway portal. Ulthran informed the Imperials that he would destroy the Blackstone Fortress, which he referred to as a "Talisman of Vaul." But to do so, he explained that he required the aid of every available vessel in the Cadia System. Seeing no other options, Creed acceded to the Farseer's request, and thenshook hands with the Eldar leader, who then disappeared back into the depths of the Webway. It galled every last member of the Cadian High Command's command council to trust the lives of so many humans to the actions of a race as duplicitous as the Eldar, but as the Farseer had said upon his parting with Lord Castellan Creed, "None of us has a choice anymore."

Battle of Kasr Partox
The valiant Imperial defenders of Cadia made their final stand upon the ramparts of Kasr Partox against the Forces of Chaos arrayed against them. A massive force of the Archenemy stood to assault the valiant Imperial defenders. The fortress city was protected by a scant 23 regiments of the Cadian Shock Troops. Alongside the regiments of Cadia stood a host of units drawn from worlds near and far, such as the Knovians, Gundronites, Mordants, Thracians, Jourans and a thousand more. The Battle-Brothers of the Adeptus Astartes were also counted amongst the Imperial defenders, including the Chapters of the Dark Angels, Space Wolves, Ultramarines, Doom Eagles and many more that are not named in the Imperial records. There were also many other servants of the God-Emperor present, including the Battle-Sisters of the Orders Militant of the Adepta Sororitas, the mighty Grey Knights, scores of Inquisitors, the siege dreadnoughts of the Ordo Reductor, the mighty God Machines of the Collegia Titanica and the Mechanicus' own cybernetic Skitarii warriors. And amongst them all, the Confessors of the Imperial Cult made their way, admonishing each and every man and woman to hold true to the Emperor.

But the Imperial defenders' numbers paled in comparison to those arrayed against them. Even from atop the mighty walls of the Kasr's Castellum, it was observed that not a single square metre of ground was not held by the defenders or trodden upon by the enemy. It seemed as if every twisted denizen of the Eye of Terror had converged before the walls of Kastr Partox.

In the ensuing slaughter, the Imperials were forced to abandon Kasr Partox and retreat towards the Caducades Sea, where they hoped to make their final stand at Kasr Gallan. At the height of the battle, a fleet of Necron vessels appeared from nowhere and assaulted Kasr Partox as well as the massive Chaos warfleet in Cadian orbit, forcing the Chaos-held Blackstone Fortress to disengage. With Kasr Partox fallen, the Imperial command and control structure was demolished. The Imperial retreat from Kasr Partox saw the most intense fighting of the 13th Black Crusade, with many thousands of lives given up so that the bulk of the Imperial forces might escape. The Imperial forces managed to make it to the Caducades Sea, leaving behind thousands of dead, their bodies defiled by the blasphemous Chaos horde. The Imperial ground forces fled aboard transport ships across the Caducades Sea, forced to abandon the bulk of their heavy equipment.

One of the last groups to leave was the Ecclesiarchal delegation, whose thousands of preachers had attended to the spiritual well-being of the Imperial forces throughout the fighting withdrawal from Partox. Some of these remained in the port, determined to preach the word of the Emperor until the very end, and their sonorous chants at times were said to drown out even the thunderous explosions of enemy artillery. A company of Space Marines from the Subjugators, whose numbers had been so reduced during their particpation in the defence of Cadia so as to threaten the very survival of their Chapter, chose to also make a final stand there, vowing to evacuate only when all else was lost. Imperial Guard engineers planted munitions at the heart of the port in order to ensure its destruction.

Battle of Cadia in Orbit
The Imperial fleet in orbit of Cadia above the valiant Imperial defenders on the ground was also gathered for its final stand, determined to gain time for the Eldar led by Farseer Eldrad Ulthran to board the Blackstone Fortress and disable it from within. If the xenos proved successful, the Imperial forces might live to fight another day. Should they fail, the world of Cadia and all who stood upon it would be scoured away by the power of the Warp unleashed upon its surface by the Blackstone Fortress moving into orbit above them. This had been Abaddon's plan all along in launching the 13th Black Crusade; everything had led to this particular moment.

Soon the battle in orbit was underway. True to their word, the Eldar's potent fleet fought side-by-side with the vessels of the Imperial Navy. The toll taken upon these combined forces of Order was fearsome indeed, but this desperate endeavour was worthy of the greatest of sacrifices, for failure meant that the Cadian Gate would lie open for Abaddon to launch his campaign against Terra and succeed where his master Horus had once failed. The details of the battle in orbit that ultimately saw the Blackstone Fortress defeated are difficult to piece together in the wake of the chaos caused to the Cadian High Command by the Imperial retreat from Kasr Partox. Admiral Quarren, who commanded the Imperial fleet that defended Cadia, reported that the bulk of his fleet was destroyed, many vessels having paid the ultimate price to ensure the Farseer of Ulthwe the time necessary to complete his vital mission. It appeared that the Farseer's vessel, the Isha'ra, penetrated deep through the Chaos fleet's lines, many of its sister warships being destroyed in the action. Once close enough to do so, Ulthran boarded the Blackstone Fortress, and has not been seen or heard from since.

At the height of this battle, it is reported that a fleet of Necron vessels appeared as if from nowhere and assaulted both the Blackstone Fortress and the Chaos warfleet. So       confused and incomplete are the Imperial records of this engagement that the Cadian High Command may never piece together the true details of how victory was won in orbit. Regardless of their reasons for doing so, the Necron ships forced the Blackstone Fortress to disengage from its approach on Cadia, and contact with it was lost soon after as it fled the Cadian System. The last the Imperial forces knew of what had happened to the so-called "Talisman of Vaul" was reported by a psyker attached to the Cadian High Command's general staff, Lieutenant Fortuna, who was struck down with a vision of Farseer Ulthran trapped within a shimmering crystal, his soul-scream echoing throughout the Warp. No doubt Imperial seers and savants would be looking to unravel this mystery for many years to come.

Yet the final outcome of the Battle of Cadia, no matter how it had been arrived at, was clear. The Forces of Chaos had seized a large portion of the surface of Cadia, but the Imperial and Eldar victory in orbit forced the Chaos warfleet to retreat back towards the Eye of Terror, giving the Imperium naval superiority in the Cadia System and the broader Cadian Gate. It provided the servants of the Emperor with the ability to keep the Forces of Chaos contained on the surface of Cadia, where ground operations slowly ground to a stalemate, with neither side able to make headway against the other. While the Imperium possessed air superiority, the Forces of Chaos' sheer numbers prevented them from being dislodged from their occupied territory.

Outcome
"Where is the Cadian and the Rhino? Where is the vox that was blaring? They have passed like Drop Pods from a Dauntless, like wind on the Caducades Sea. The days come down in the Wastes behind the Hives, to shadow...How did it come to this?"

- Lord Castellan Ursarkar Creed, on the eve of the final assault on Cadia

Darkness Descends - A Limited Chaos Victory
Darkness had fallen across a hundred worlds, and for the defenders of the Cadian Gate, the pure light of day now seems but a distant memory. Though the forces of Abaddon the Despoiler have been denied the ultimate prize of the fall of Cadia, Abaddon’s hordes have gained a foothold upon the worlds of Mankind for the first time in over 10,000 standard years, and none can see them being repelled for many years to come. Abaddon and his Council of Three have outmanoeuvred and outfought the forces of the Imperium at almost every turn. Corpses litter the battlefields in their millions, yet millions more still stand beleaguered, against a foe that knows no mercy and whose only goal is the utter destruction of all who stand before them. The bleak moors of Cadia have been reduced to a barren, crater-pocked wasteland, blasted by orbital torpedoes, super-heavy artillery and the massive footfalls of Titans.

The Vilklas and Andur defence lines have collapsed under the relentless pressure of a million frenzied Chaos Cultists, Traitors and mutants, and the Cadian Sector High Command has been forced to relocate to Kasr Gallan on the far side of the Caducades Sea. Though the Imperial Navy is in control of the inter-system space lanes of the Cadian Sector, the Forces of Chaos still maintain a powerful presence in the skies directly above Cadia that is capable of challenging the Imperial fleet since the Imperial orbital defences fell in the opening days of the 13th Black Crusade. The defenders of Cadia are now deployed around Kasr Gallan and throughout the Wastes, resolute that not a backward step shall be taken. The order has been given: "Stand at Cadia, or damn the Imperium of Mankind to the depredations of Chaos for all eternity."

The long-held dominance of the Imperium in the Segmentum Obscurus has been decisively shattered. Chaos forces roam freely on the once proud worlds of Scarus, Agripinaa, and even within the Cadia System. Whole worlds have fallen to the tide of Disorder that has swept across the sectors of the segmentum. Abaddon's 13th Black Crusade appears to have been a modest success. Although he cannot claim complete dominion over the Cadian Pylons, the damage and chaos inflicted upon the Imperium will have severely weakened its activities within the segmentum long into the new millennium. Commanded by the shadowy Triad, the the council of Chaos Champions that controls the Planet Killer, and groups of dedicated tacticians, the servants of the Ruinous Powers have come away with a win. It is a slim win, but a win nonetheless. The desperate actions of a few heroes within the Imperial hierarchy have, however, held the Forces of Chaos at bay in several sectors and star systems, claiming outright victory in most of the outlying sectors, and preventing total catastrophe for the Imperial forces in the inner sectors of the segmentum.

Though Abaddon's final goal of smashing through the Cadian Gate was ultimately unsuccessful, the advances made by his forces have gained him much more than was initially realised. His retinue of Chosen, led by Devram Korda, the Tyrant of Sarora, returned to his side in the closing days of the war, bringing with them two individuals who had journeyed to the centre of the Eye of Terror. Together with the Chaos Sorcerer, Ygethmor the Deceiver, they presented Abaddon with the Heart of Chaos, a powerful Chaos artefact that Zaraphiston, the Chaos Sorcerer who served as one of Abaddon's Chosen, had long claimed could not exist. It is known that Ygethmor now stands at Abaddon's right hand, while Zaraphiston's status remains a mystery.

Cadian Sector
The Fortress World of Cadia still stands, but she stands alone, a failing beacon of the Emperor's light flickering against the encroaching night. Total war has come to the Segmentum Obscurus, and all hopes of repelling the invaders have been dashed for the moment. The Imperium must now consolidate its grip upon those worlds of the segmentum it still holds, and prepare to fight a war that will not end within the lifetime of any of its combatants. While Cadia still stands, humanity has reason to hope, but Abaddon the Despoiler has finally achieved what he had failed to do on twelve previous occasions, over more than ten thousand standard years -- he has breached the Cadian Gate, and none can now hold back the eventual tide of Chaos he will seek to unleash upon the Imperium of Man.

The Forces of Chaos won a small if significant victory over the Imperium and the Eldar, capturing a number of Imperial worlds in sectors beyond the Cadian Gate for the first time since the Horus Heresy. Cadia still stands, but only just, as most of the planet's surface belongs to Chaos. The battle for Cadia will last centuries without aid, but if Chaos gains headway in the space above Cadia, then the defenders will be doomed, especially with a Blackstone Fortress still lurking somewhere. Even without aid to the Imperial forces in orbit, there is a large chance that simple supplies such as food will be unable to reach the defenders, and that the defenders will eventually starve to death. No man, no Space Marine, fought harder to save Cadia than the Lord Castellan Ursarkar E. Creed. Although each Castellum levelled cut him deep, the faith of Ursarkar Creed proved unshakeable. His victories could not easily be counted, but the numbers of the Archenemy did not lessen whereas each defeat drained the strength of the Imperial forces. Creed was forced first to give ground to preserve his forces and then to abandon his favoured mobile defensive tactics in favour of defending fortified lines. His friend, Jarran Kell, was wounded defending him from yet another Chaos Champion eager to make a name, and Creed was fatigued to the point of collapse when finally the momentum of the Chaos forces ran out.

The Inquisition Fortress World of Nemesis Tessera, its existence supposedly unknown to all but the highest members of the Inquisition, came under fierce attack during Abaddon's 13th Black Crusade. The systems surrounding the Inquisition Fortress World experienced hitherto unknown levels of civil insurrection that could not be explained without recourse to the malign influence of the Ruinous Powers. In one such incident, a previously peaceful sect of contemplative monks turned on the populace of the nearby planet Trionora, engaging in a series of bloody massacres across the planet's surface. Ordo Hereticus strike teams were dispatched to cull these killing sprees -- they discovered the barricaded monasteries to be full of corpses, the monks having chosen to end their lives in an orgy of self-mutilation. The monasteries were burned to the ground, the ruins sown with salt and reconsecrated.

While the agents of the Inquisition policed the systems surrounding their fortress, many strange omens and portents were unearthed, all indicating great disaster. Many believed this simply to be the foretelling of the invasion of Abaddon, but other, more cautious Inquisitors believed it to be something more. These doomsayers were proved correct when the blind servers of Nemesis Tessera detected unauthorised psychic activity within the depths of the fortress itself. Inquisitor Van Hel, a Radical Inquisitor who delved too deeply into mysteries best left alone, had been seduced by the whispered promises of the Ruinous Powers and only the timely intervention of Inquisitor Cyarro prevented a Warp rift of cataclysmic proportions from developing. At almost the exact same time, a determined force of Chaos Space Marines launched an attack on the Inquisition fortress and laid siege to it for many months. Only the timely arrival of the Space Wolves saved the beleaguered Inquisitorial forces and the combined forces of the Inquisition and the Sons of Russ were finally able to repulse the attack. The reason why the Space Wolves abandoned their previous station to deploy throughout the Nemesis Tessera Sub-sector remains a mystery.

Scarus Sector
During Abaddon's 13th Black Crusade, the Warmaster of Chaos Undivided recruited massed warbands of Orks to act as mercenary auxilia to his Chaos Legions. Following up on terror raids and cunning feints by the Night Lords and Alpha Legion, many of the Orks banded together into ever-growing tribes that declared themselves to be a part of the "Green Kroosade." The unstoppable force of the Green Kroosade inundated the Scarus Sector (Skar-Uz to the Orks), battering down Imperial defences with sheer doggedness and not without a little help from the Chaos Space Marines, particularly those of the Night Lords and the Black Legion. Now the Orks rule both the worlds of Lethe XI and the Forge World of Mordax Prime, along with most of Imbrium and Ulant. Gudrun and Nysa Stromolo stand on the brink of anarchy and the weapon forges of Mordax Prime (rechristened "Moredakka" by the Orks) are infested with lootas of the Death Skulls klan, a truly terrifying prospect to the devotees of the Machine God, who know full well the depths of blasphemy against the Omnissiah to which these barbaric xenos will sink.

Bartered survivors speak of hundreds of Gargants being built from the debris of war by enslaved Servitors and their brutal Greenskin overseers. The squat, menacing forms of more Gargant construction sites climb over the plains of Mordax dairy as Ork Mekboyz race to be the first to complete their war machines. Imperial stategists now regard the Green Kroosade as a full-scale Ork WAAAGH! Its commanding Warlords remain unknown, but it would appear that Ghazghkull and Nazdreg are not among them. Only Thracian Primaris holds firm against the "Green Kroosade," bolstered first by the intervention of a Black Templars Crusade, and later by the stalwart defence mounted by the Salamanders Chapter. The situation is grim in the Scarus Sector, and none can see an end to the infestation given the dire situation across the region.

Scelus
Scelus was the homeworld of the Renegade Space Marines of the Sons of Malice Chapter, and was declared Perdita at the time that Chapter turned upon the Imperium. A cold, desolate place, Scelus is home to the savage and barbaric tribes from which the Sons of Malice recruited their number. Though reports from the front line at Scelus are unclear on the subject, reliable sources state that the invading Forces of Chaos joined with the native tribes, establishing a potentially huge power base within a short space of time at a strategically vital location.

The forces of the Imperium were in no position to oppose this state of affairs in the initial stages of the invasion, as every available Imperial Guard regiment was committed elsewhere and none could relocate swiftly enough to oppose Abaddon's plans for Scelus. However, Abaddon's plans were in fact opposed, and very soon the Imperium was in full control of Scelus, having slaughtered the invaders without mercy. The exact identity of the Imperial forces that liberated the system is unclear, though this is far from unusual in a region within which uncounted millions of soldiers are fighting, with more arriving every single day. That the liberators were Space Marines is known, though the exact Chapter is not. It was reported that several Chapters were located within a short Warp jump to Scelus in the days leading up to its liberation, including the Night Watch, the Subjugators and the Howling Griffons.

Nothing has been heard from any Imperial forces in the area, and it is suspected by some that a Space Marine Chapter has claimed Scelus as its homeworld by right of conquest. In the current climate, none in the Segmentum Obscurus High Command would argue against such a move.

Belis Corona Sector
The Imperial forces have largely held at Belis Corona, the location of the greatest shipyard of the Imperium, which suffered the worst excesses of a Tyranid splinter Hive Fleet, and the horrific plagues bestowed upon its hive cities by the Death Guard Traitor Legion. At the height of the invasion, something truly unexpected occurred. Defenders in the outlying systems reported contact with Tyranid organisms -- at first individual vanguard-organisms such as Lictors, but soon entire broods of Genestealers and Hormagaunts. A splinter fleet of Hive Fleet Leviathan, a Tyranid fleet known to be attacking up through the galactic plane, was taking advantage of the mass destruction initialed by the Chaotic invasion to gain a foothold in strategically vital Imperial space. Faced with both the pestulant forces of the Death Guard, and the voracious hordes of Tyranids who were, unlike the human defenders, immune to the Plague God's blessings, the forces of the Imperium were hard-pressed to defend the vital worlds of the sector. It was the intervention of the forces of the Eldar of the Ulthwé Craftworld and then the orbital bombardment of Laurentix that allowed the forces of the Imperium to fight back, despite the disastrous ambush of forward elements of Battlefleet Solar at the Bairsten Prime Warp jump point. Subiaco Diablo saw the Convent of the Order of the Ermine Mantle hold out against overwhelming odds, though at terrible cost, before being relieved by a host of Adepta Sororitas units drawn from across the region, thanks to the leadership of the renowned Canoness Astra.

Agripinaa Sector
The industrial heartland of the Cadian Gate lies in ruin. Though the Imperial Navy controls its space, many worlds of the Agripinaa Sector are lost to anarchy and destruction. By the end of the war, the planets Albitern, Amistel, Lelithar, Malm's Reach, Ulthor and Yavor lay in ruins, and a number of other key star systems hung in the balance. Though Agripinaa itself still stands, without the Agri-Worlds of Yayor, Ulthor and Dentor, its populace may yet starve to death, and without the vital materials provided by the Hive Worlds of Albitern, Amistel and Tabor, its mighty forges may yet fall silent. The so-called "Herald of Nurgle," Typhus of the Death Guard Traitor Legion, has claimed the now blasted world of Ulthor as his own realm, and the nightmare visions of a thousand Astropaths tell of the birth of a new Daemon World within the realm of Mankind. Further, unconfirmed reports state that one of the Blackstone Fortresses was destroyed by Necron raiders off the shoulder of the Lustitia Belt. Senior members of the Ordo Xenos are en route to the area, and Deathwatch Strike Cruisers are already engaged in ensuring no vessels other than their own enter the region. Striding through the blackened ruins of the ravaged worlds of the Imperium, crushing the bones of the slain beneath his Chaos Terminator Armour and spreading the vilest afflictions of Nurgle, Typhus was the embodiment of terror, a cursed thing too terrible to name. His ship, the Terminus Est, and its supporting Plague Fleet were one of the largest Chaos battle groups remaining active throughout the war and allowed Typhus to terrorise warzone after warzone. It was on the world of Ulthor in the Agripinaa Sector, that Typhus unleashed his greatest sorceries, exhibiting the great favour in which he is held by Nurgle. The once verdant Agri-World was utterly twisted and corrupted. The taint of the Herald devolved whatever life it found, rendering it down into a formless sea of putrescence. Seeing his handiwork, Typhus took the nascent Daemon World for his own, a stronghold beyond the Cadian Gate from which he can bring terror to the other worlds of the Imperium at his leisure.

Sentinel Worlds
The barren Sentinel Worlds in the southwest quadrant of the Eye of Terror have always been thought to be a collection of mostly featureless rocks held together by specific gravitational anomalies. The Adeptus Mechanicus have done much to discourage development in this region due to their facility stationed on Hydra Cordatus, a relatively unremarkable planet holding a potent secret -- it was one of the few locations in the galaxy where the Adeptus Mechanicus stored its tithes of Space Marine gene-seed, in this case genetic material drawn from the Imperial Fists Chapter. The planet consisted of only a spaceport and a single large citadel and manufactorum complex known as the Tor Christo. The Tor Christo was a large star-shaped fortress connected to a smaller half-star fortress built into the side of a nearby mountain. The citadel had a large garrison of Imperial Guard troops and even a small Titan Legion contingent from the Legio Ignatum, to protect its precious contents. Remaining undisturbed for centuries, there were unconfirmed reports of a great Iron Warriors invasion into the system, preceding even the Hive Teriax disaster in the opening phases of the 13th Black Crusade.

During the siege of the large Imperial citadel and manufactorum complex on Hydra Cordatus, a faint psychic beacon was transmitted from the surface of the planet. The Iron Warriors warband's flagship Stonebreaker was sent to the star system's Warp translation point in order to intercept any Imperial reinforcements. But this action allowed an Imperial Fists company to slip past the flagship and infiltrate the planet's surface and reinforce the besieged Mechanicus garrison. Inevitably, the Iron Warriors emerged triumphant. They defeated the Imperial forces defending Tor Christo as well as the Imperial Firsts company. Having greatly pleased the Chaos Gods through his monumental victory over the Imperium, the commanding Warsmith of the attack on Hydra Cordatus was ascended to become a Daemon Prince.

During the opening stages of the 13th Black Crusade, the Sentinel Worlds had little in the way of full-scale engagements, although a node in the Webway stationed above these worlds saw a lot of conflict between the Eldar and their Chaotic enemies. The most notable development emerged from this unregarded backwater sector just as the war reached its peak, with hordes of silvered Necron warriors emerging from hidden tombs on the four planets surrounding Hydra Cordatus in a rough pyramidal pattern. The Imperial forces stationed nearby feared the worst, but were amazed when the Necrons fell upon the warriors of Chaos, turning the tide in favour of the Imperium. Since that time, increased Necron activity in the sector has prevented any Imperial forces from capitalising upon these victories, and remote orbital pict-captures have even revealed several structures almost identical to the Cadian Pylons sprouting across the landscapes of these four Sentinel Worlds.

Chinchare Sub-sector
Imperial forces largely ignored the mostly uninhabited Chinchare Sub-sector in the early stages of the war, though the forces garrisoned throughout the region were hard-pressed to contain the initial surge of Chaotic invaders. Reports of increased Chaos activity drew more forces there as the war went on and the Eldar forces of Ulthwé fought hard and spilt much blood in order to wrest control of the sub-sector from the Ruinous Powers. Ulthwé Strike Forces struck at key points within the systems surrounding Chinchare to deny the forces of Abaddon any cohesion to their armies. Striking behind the lines of the main Chaos thrust, precious resources were diverted from the Forces of Chaos' frontline to deal with the raiding Eldar in the rear. Those forces dispatched to deal with the Eldar were themselves ambushed and destroyed piecemeal. Such superiority brought with it an arrogant belief that the Eldar strike forces were invulnerable, but such was not to be the case as Ahriman, the Thousand Sons Chaos Sorcerer, wove powerful magicks to disrupt the path of the Webway, twisting it and ripping portions of it asunder.

Much was the lamentation of Ulthwé as many of the Craftworld's strike forces were trapped forever in the Webway or lost in the haunted depths of the Warp. While Ulthwé reeled from these terrible losses, the Chaos forces pressed their attack and launched a devastating counter-attack against Imperial forces, particularly those based on Balzac. The Imperial troops were in danger of being overrun completely, before being suddenly and decisively aided by Eldar emerging from shimmering Webway portals. These mysterious benefactors asked nothing in return for their aid and vanished without a word of explanation. As more and more reports were collated, it appeared that these silent Eldar had appeared virtually simultaneously throughout the Sub-sector, effectively stymieing the Chaos attack. As the Chaos forces reeled, the vengeful Eldar, combined with the might of the Imperial forces, were able to rout the followers of the Dark Gods from the Chinchare Sub-sector completely.

The Relictors
As a result of the actions of the recalcitrant Chapter known as the Relictors and their conflict with the Inquisition over the use of Chaotic artefacts, the Relictors were judged to be Extremis Diabolus, their lives forfeit. The decision was swift and unanimous and the Chapter was ultimately declared Excommunicate Traitoris by the Ordo Hereticus. The Relictors had turned from the Emperor's Light and were to be hunted down and destroyed; their gene-seed wiped from the galaxy and all record of their deeds expunged from Imperial history. The Relictors had lost a great many of their number during the 13th Black Crusade and their mobile fortress-monastery, a Ramilies-class Starfort, had been severely damaged during the recapture of the world of Finreht. It had taken all the skill of the Chapter's Master of the Fleet to secretly move them to anchor in the Taeloth System, where they attempted to recover their strength and make use of the knowledge they had gleaned from the dark treasure they had recovered within the Diamedes Archive. The Chapter was all but destroyed in a cunning ambush by the Ordo Malleus' Chamber Militant, the Grey Knights, under the command of Inquisitor Cyarro, whom the Relictors had left for dead on the Agri-World of Fremas. After assaulting their fortress-monastery, the assembled Inquisitorial fleet hammered the dying remains of the Relictors' Starfort with concentrated fire from their powerful gun batteries. A Ramilies Starfort is a massive edifice and took time to fully destroy, but the Inquisition left only when every trace of the Relictors was reduced to dust. Only a few hundred Relictors Astartes survived this assault, and it is suspected that these renegade Space Marines have fled to the relative safety of the Eye of Terror. It is currently unknown whether these survivors have thrown in their lot with the Forces of Chaos and become full-fledged Chaos Space Marines or whether they continue their struggle of trying to turn the dark powers of the Chaos Gods against them and their servants for the good of humanity, much like another well-known Renegade Space Marine Chapter, the Soul Drinkers.

Dark Angels
Caliban was the site of many bitter battles throughout the war, and the Dark Angels Chapter was forced to defend the ruins of their former homeworld against the blasphemous hordes of the Abaddon the Despoiler, who were intent upon desecrating the holy ground. But, despite the vindictive campaign of lies and profanity conducted by the heretic known to his followers as the "Voice of the Emperor," which were seemingly designed to draw the Dark Angels into pointless battles away from the main fronts, they did in fact prove invaluable in many conflicts across the region - despite the generally held view that the Dark Angels and their Successors (collectively known as the Unforgiven) fought exclusively and selfishly for the ruins of Caliban while Cadia burned.

At the close of the war, Caliban was firmly in the hands of the Dark Angels, its secrets safe for the time being. The Dark Angels had not only held Caliban against continuous attack, but were able to counter the activities of a number of the Fallen Angels, better known as the Fallen -- the rogue brethren who the Chapter and its UnforgivenSuccessors have relentlessly hunted to the exclusion of all other considerations for ten millennia. The so-called "Voice of the Emperor" put much effort into sewing disunity amongst the defenders of the Cadian Gate, seeding doubt as to just what the Chapter was hiding amongst the frozen ruins of its homeworld. Rumours abound that the Dark Angels have since captured the "Voice of the Emperor" himself, only for this mysterious Heretic to escape his prison en route to the Tower of Angels. Other rumours suggests that Lord Castellan Ursarkar Creed now harbours a deep resentment towards the Chapter, whose presence, he feels, might have proved critical in the defence of Cadia in the most desperate phases of the war, were the Chapter not focusing its efforts upon Caliban. Having suffered the presence of the servants of the Ruinous Powers, the holy places of the Caliban System have now been reconsecrated by the most senior Interrogator-Chaplainsofthe Chapter, and it is clear that, whatever the result of the larger war, no devotee of Chaos shall ever again approach within a light year of the Caliban System again. The mysterious leader of the Fallen, Cypher has been hunted by the Dark Angels and their Successor Chapters for ten thousand years. Though it is not known whether Cypher was encountered directly during the war, unconfirmed reports suggest the Chapter's Interrogator-Chaplains captured as many as 8 Fallen during the battles around the Caliban System, more than have been captured in such a short period in many thousands of standard years. Further reports link Cypher to the mysterious "Voice of the Emperor" on the world of Lelithar, who, it is rumoured, was captured by the Dark Angels during the fighting, but whose cell was found empty upon the prison ship's return to the Tower of Angels aboard the Dark Angels vast, mobile Fortress-Monastery known as The Rock. Azrael, the Supreme Grand Master of the Dark Angels, was a notable absentee at the council of Chapter Masters that elected Logan Grimnar their head at the start of the 13th Black Crusade. Azrael led the Dark Angels, and the so-called Unforgiven Chapters, according to his own, inscrutable strategy. The only time he is known to have stood beside other Imperial forces was when he led a company of Dark Angels upon Xersia, where he joined with Lord Castellan Creed and his 8th Cadian Regiment to repel a force of Black Legionaries from the world's High Basilica, though Abaddon succeeded in his sacrilegious mission to desecrate the high altar as part of some dedication to the Ruinous Powers that would guarantee the success of the 13th Black Crusade. Azrael was instrumental in repelling the invaders, for a time at least.

The Space Lanes
The Imperial Navy had fought with courage and vigour throughout the war, ruthlessly taking the battle to the Archenemy wherever it encountered them. Admiral Quarren had been hailed as a true hero of the Imperium for his masterful defence of the space lanes was all that stood between survival and utter defeat for the Imperium. Though Cadia was besieged, the Imperial Navy continued to command its space and the space of all the sectors surrounding the Eye of Terror, and was able to offer support to beleaguered forces on the ground. The only question is whether the rapid redeployment of almost the entirety of Battlefleet Gothic, along with a substantial proportion of Battlefleet Solar, will leave the Imperial Navy dangerously overstretched elsewhere and unable to maintain the level of operations required to hold the line at the Cadian Gate.

The Tau Empire
The Tau made several major expansions to their empire over the course of the 13th Black Crusade. If any one race or faction can said to have gained from the wholesale destruction unleashed by Abaddon the Despoiler's campaign, it was the Tau. With Imperial attention was elsewhere, and the local Tyranid and Ork menace temporarily contained, Tau settlement colonies and pioneer teams reached far and wide into the outlying systems of the Eastern Fringe in the Damocles Gulf, the Perdus Rift and much further afield. Although the encroachment on Imperial space has been relatively minor, the Tau have established no fewer than five Third Sphere Expansion colony systems in a halo around their existing Sept Worlds. These areas of expansion are already being referred to as the Third Sphere Colonies by the diplomats of the Tau Water Caste, and are rumoured to include unprecedented numbers of human auxiliaries. That the Imperium's attention is focused elsewhere is no doubt of comfort to those humans who have pledged their support to the burgeoning Tau Empire. The Third Sphere Expansion was only finally halted in 999.M41 as a result of the Zeist Campaign waged against the Tau by an alliance of Space Marines, as described above.

The Webway
The Chaos Sorcerer Ahriman himself ripped open the walls of the Webway with information torn from the mind of Inquisitor Bronislaw Czevak. His plan to breach the fastness of the Black Library came dangerously close to success, but the combined forces of the mysterious Harlequins and an Ulthwé Strike Force kept him from its gates. In a daring move, the Harlequins of the Red Masque freed Inquisitor Czevak from his captivity aboard Ahriman's flagship, the Impossible Fortress. Though what they have done with him since, is, at present, unknown: it is believed by Imperial Astropaths that he may be incarcerated by the Eldar within the Webway.

The Eldar have re-sealed the Webway against all invaders, expelling the Traitor Space Marines of the Thousand Sons Legion, and rebuffed their own wayward kin, the Dark Eldar, back to their shadow-realm of Commorragh. For now, the hidden places of the Eldar, and the terrible secrets they hide, are safe from the predations of the "lesser races." Those warzones only accessible through the Webway are now held by the Eldar, including the ancient Crone World of Belial IV, a former jewel in the once-mighty galaxy-spanning Eldar empire.

Belial
Aeons ago, the Crone World of Belial IV was a capital world of the ancient Eldar empire. Deep in the heart of the Eldar homelands, this verdant paradise was all but obliterated when the cataclysmic Fall of the Eldar stripped away thousands of years of culture and beauty and replaced it with madness, desolation and evil. Belial IV became a dust-strewn wreck of daemon-infested ruins and crackling, baleful skies. Maugan Ra, a Phoenix Lord and therefore a veteran of Webway travel, braved the depths of the Eye of Terror on a pilgrimage to the shattered Crone Worlds, intending to find a faction of Eldar he believed trapped within the Eye of Terror since the Fall. Taking with him a few of his favoured disciples, Maugan Ra eventually reached the Hex System of Belial IV. What he found there he would not speak of and he was not seen again until he appeared upon Ulthwé to form the infamous Eldar Strike Forces, filled with renewed energy and determination to defeat the Forces of Chaos.

Towards the end of the 13th Black Crusade, many of the Eldar departed from warzones in Imperial space and gathered upon Belial IV under Maugan Ra's command. They took the fight to the indigenous Chaos forces with such unremitting fury that vast areas were reclaimed by the Eldar. The battle also raged around Belial IV in the Labyrinthine Dimension of the Webway, but it seemed that without the guidance of their leaders the Ulthwé Strike Forces suffered heavy losses to both the Dark Eldar and the Thousand Sons. The otherworldly guardians of the Black Library, fearing for their shadowy rCraftworld's safety, revealed hitherto unknown capillaries of the Webway to the Ulthwé Eldar, enabling them not only to escape from the net drawing around them, but to stage a series of ambushes that broke the deadlock and turn the tide of the war in the Webway once and for all.

The final, and most decisive, twist to this peculiar theatre of war came when a daemon horde led a counter-attack against the Eldar consolidating their hold on the Crone Worlds, as sudden as it was devastating. To the great shock of the Eldar below, the withered and broken Craftworld of Altansar, thought lost to the Warp for more than 10,000 Terran years, drifted into orbit above the Crone Worlds. Hundreds of pallid, ghost-like Eldar joined their brethren on the field of battle, throwing back the daemon tide with wave after wave of silent, grim warriors. Since that great victory, Belial IV has been reclaimed by the Eldar. What this, and the reappearance of the Lost of Altansar, bodes for the Eldar race remains to be seen.

Maugan Ra
The immortal Phoenix Lord Maugan Ra took a vital role in deciding the fate of the Eldar over the course of the 13th Black Crusade. Responsible for the creation of the Ulthwé Strike Forces, Maughan Ra and his elite Black Guardians fought across every sector by cunning use of the Webway. He ultimately led the Eldar to victory even in the heart of the Eye of Terror and, after repelling Dark Eldar raids on Xersia, fought alongside Lord Castellan Ursarkar E. Creed against Abaddon's forces at the Basilica Dufaux. It is believed by many Farseers that the reappearance of the shadowy Craftworld of Altansar and its ghost-like inhabitants was purely due to the iron determination of the Phoenix Lord to locate and redeem his once-lost brethren.

Eidolon
The mysterious world of Eidolon, deep in the heart of the Eye of Terror, is one of the most remote and peculiar of the Daemon Worlds fought upon during the 13th Black Crusade. Divided into several continents where a different Chaos Power reigns over each, the battlezones of Eidolon present a panoply of strange and excruciating ways to die. Its shifting landscapes defy all reason, and, although it was once a beautiful Maiden World of the Eldar, it has changed so irrevocably that no real trace of its former glory exists. Nonetheless, the victories won by the Eldar, notably the Eldar of the Biel-Tan Craftworld, have established several enclaves of sanity in the roiling seas of possibility that characterise Eidolon. The Eldar hope that one day these islands can grow and become stable, and that eventually the secrets of Eidolon can be reclaimed.

Fate of Eldrad Ulthran
For the Farseer Eldrad Ulthran, the most gifted and powerful of all the Eldar Seers, the onset of the 13th Black Crusade meant that the twisting forests of possibilities through which he normally walked at will were denied to him, blinding his exceptional scrying abilities. His one certainty was that darkness stood ready to engulf him and possibly even his home Craftworld of Ulthwé. After the formation of the Ulthwé Strike Forces, Eldrad divided many parts of his consciousness into shimmering Waystones. As for Eldrad Ulthran's fate, this bravest and most noble leader of the Eldar since before the birth of Slaanesh has perished. In a last-ditch effort to stop the Blackstone Fortress ("Talisman of Vaul") controlled by Abaddon from crushing the Imperial defenders of Cadia, he and a select few Warlocks teleported aboard. Within minutes, all the Warlocks were drained of life by the Fortress' bottomless thirst, and when Eldrad reached out to try to touch the Eldar spirit that he believed comprised the core of the Fortress' sentience, he found only an extension of the hideous mind of Slaanesh -- "She Who Thirsts," the Great Enemy of the Eldar. As Eldrad realised his folly, his soul was devoured by the Chaos God inhabiting the Blackstone Fortress, and the greatest Farseer of the Eldar was lost. However, a handful of Waystones that Eldrad had created still remained active, causing the Eldar to believe that Eldrad is still alive but trapped somewhere in the Warp, perhaps at the mercy of Slaanesh.

Senior Command

 * Ursarkar E. Creed - Lord Castellan of Cadia and overall Imperial Commander of the defence of Cadia.
 * Logan Grimnar - Great Wolf (Chapter Master) of the Space Wolves Chapter and overall commander of the Adeptus Astartes forces in the Cadian System. A council of representatives from those Chapters of the Space Marines opposing Abaddon's 13th Black Crusade elected the irascible Great Wolf as their nominal head.
 * Admiral Quarren - Commander of Battlefleet Cadia and overall commander of Imperial Navy forces, Admiral Quarren has been hailed a true hero of the Imperium, for his masterful defence of the space lanes was all that stood between survival, and utter defeat for the Imperium. Though Cadia is besieged, the Imperial Navy commands space, and is able to offer support to beleaguered forces on the ground. The only question is whether the rapid redeployment of almost the entirety of Battlefleet Gothic, along with a substantial proportion of Battlefleet Solar will leave the Navy dangerously overstretched elsewhere and unable to maintain the level of operations required to hold the line at the Cadian Gate.

Chapters of the Adeptus Astartes

 * Angels of Absolution - 10 Companies
 * Angels of Vigilance - 5 Companies
 * Angels Sanguine - 7 Companies
 * Blood Angels - 4 Companies
 * Brazen Claws - 10 Companies
 * Dark Angels - 10 Companies
 * Death Spectres - 6 Companies
 * Doom Eagles - 5 Companies
 * Excoriators - 8 Companies
 * Exorcists - 10 Companies
 * Harbingers - 8 Companies
 * Howling Griffons - 8 Companies
 * Imperial Fists - 5 Companies
 * Iron Hands - 10 Clans
 * Iron Knights - 1 Company
 * Iron Snakes - 5 Companies
 * Marines Exemplar - 9 Companies
 * Night Watch - 11 Companies
 * Novamarines - 6 Companies
 * Relictors - Declared Excommunicate Traitoris by the Inquisition during the 13th Black Crusade
 * Revilers
 * Space Wolves - 12 Great Companies
 * Storm Warriors - 10 Companies
 * Subjugators - 3 Companies
 * Ultramarines - 1 Honour Company
 * White Consuls - 10 Companies
 * White Scars - 10 Companies

Companies

 * Space Wolves 13th Company

Orders Majoris

 * Order of the Bloody Rose - 6 Preceptories
 * Order of the Ebon Chalice - 4 Preceptories
 * Order of Our Martyred Lady - 5 Preceptories

Orders Minoris

 * Order of the Divine Lamentation
 * Order of the Ermine Mantle - 3 Missions
 * Order of the Maurdlin Countenance 
 * Order of the Silver Lily
 * Order of the Sublime Adoration
 * Order of the Wounded Heart - 1 Commandery

Notable Regiments

 * Agripinaa Home Guard
 * Avellorn Field Regiments
 * Avellornian Gunners - 32 Squadrons
 * Bar-El Penal Legions - 4 Legions
 * Blitzen Heavy Armoured
 * Cadian Shock Troops - 612 Regiments
 * Cadian Youth Army - 36 Regional Commands
 * Cadian Kasrkin - 486 Companies
 * Catachan Jungle Fighters
 * Cthonian Armoured Cavalry
 * Death Korps of Krieg
 * Drookian Fenguard -16 Companies
 * Finreht Highlanders - 3 Regiments
 * Gudrunite Rifles - 47 Regiments
 * Jouran Dragoons - 7 Regiments
 * Kellersburg Irregulars - 3 Regiments
 * Knovian Gharkas - 14 Regiments
 * Mordian Iron Guard
 * Necromundan 8th, "The Spiders" - 1 Regiment
 * Narmenian Tank Brigades
 * Narsine Yeomanry - 32 Battle Groups
 * Praetorian Guard
 * Thracian Guard - 35 Regiments
 * Valhallan Ice Warriors
 * Van De'Man's World, "Redbacks" - 5 Regiments
 * Zenonian Free Companies - 9 Companies

Individual Regiments

 * Abyssian IX
 * Agrapinaa 67th Armoured Rifles
 * 17th Alasia Prime Mobile Infantry
 * 4th Alba Highland Militia
 * Aldarriss 1st
 * Alderia Royal Guards
 * Alloran 5th
 * 101st Amalgamated Regiment
 * Amaquan 1st
 * Ambrosian 35th
 * Arborean Prime
 * Arcturan 23rd Regiment
 * 2nd Ardelan Rangers
 * Arkaddian XXIV Irregulars
 * Armageddon Steel Legion 37th
 * Armageddon Steel Legion 23rd
 * Arxan 4th Rifles
 * Asarkin Mobile Infantry
 * Attredan 5th
 * 5th Augusta
 * XIII Aurech Irregulars
 * Aurellian XIV
 * Azin 2nd
 * 9th Balakovo Guards
 * Bakka Sector Task Force
 * Bakkan Battlegroup Hydrax
 * Baraduun Keep
 * Barbarossan 125th Infantry Regiment
 * Battlegroup Deitweiler
 * Battlegroup Gael
 * Battlegroup Imperatis
 * Battlegroup Maxima
 * Battlegroup Nemesis
 * Battlegroup Primus
 * Battlegroup Tempest
 * Bavarian 6th Army
 * Bethus 28th Light Expeditionary Force
 * Bifrost 121st Regiment
 * 17th Bolshev Guard
 * XLVII Boroeal Regiment
 * 79th Britan Armoured Reconnaissance Regiment
 * 122nd Bushrats
 * Cadian 734th
 * Cadian 556th
 * Cadian 477th
 * Cadian 379th
 * Cadian 377th
 * Cadian 366th
 * Cadian 223rd
 * Cadian 204th
 * Cadian 173rd
 * Cadian 148th
 * Cadian 135th
 * Cadian 131st
 * Cadian 123rd
 * Cadian 122nd
 * Cadian 121st
 * Cadian 107th
 * Cadian 102nd
 * Cadian 107th
 * Cadian 95th
 * Cadian 75th
 * Cadian 69th
 * Cadian 52nd
 * Cadian 47th
 * Cadian 45th
 * Cadian 42nd
 * Cadian 39th
 * Cadian 33rd
 * Cadian 32nd
 * Cadian 27th
 * Cadian 23rd
 * Cadian 22nd
 * Cadian 20th
 * Cadian 14th
 * Cadian 13th
 * Cadian 12th
 * Cadian 10th
 * Cadian 9th
 * Cadian 8th
 * Cadian 7th
 * Cadian 4th
 * Cadian 3rd
 * Cadian 120th Armoured 
 * Cadian 9th Armoured
 * Cadian 4th Old Guard
 * Calax Vlll Regiment
 * Calexian 7th
 * Calmonian 198th
 * Cambreadth 7th
 * Camden 223rd
 * Canteral V
 * Caracan 132nd Armoured
 * 4th Carillian Armoured Infantry
 * Carolon Guards
 * Carothian 313th Regiment
 * Carthago 3rd
 * Castellans 12th
 * Catachan DI (501st)
 * Catachan CCCXXIX (329th)
 * Catachan CCCXXIII (323rd)
 * Catachan CLXXXI (181st)
 * Catachan CXII (112th)
 * Catachan XXXVII (37th)
 * CatachanXXXII (32nd)
 * Catachan XXII (22nd)
 * Catachan XVII (17th)
 * Catachan XV (15th)
 * Catachan XII (12th)
 * Charon 492nd Mechanised
 * 39th Chelsean
 * Chudian 1st Armoured
 * Cimmerian 6th Regiment
 * Coban III
 * Comagran 1st
 * 1st Combine Replenishment Battlaion
 * Corican 101st
 * Corthasian Expeditionary Force
 * Corvus 23rd
 * Crinan Ivth
 * Dalarian 3rd
 * 35th Daltigoth Irregulars
 * Danko's 114th
 * Darien 54th Volunteer Infantry
 * Darilian XVII
 * Death Korps of Krieg 88th
 * Death Korps of Krieg 27th Grenadier Guard
 * Death Korps of Krieg 23rd
 * Dernhelm 9th
 * 153rd Desert Devils
 * XII Diddiane Dragoons
 * Dogs of KaBahh
 * 9th Dominicus
 * Drepanan 212th
 * 122nd Drookian Fenguard
 * Dterian 125th Regiment
 * Durellian 4th
 * 97th Eisen Irregulars
 * 156th Elysian Drop Troops
 * 158th Elysian Drop Troops
 * 101st Elysian Drop Troops
 * 41st Elysian Drop Troops, "Angel Guard"
 * 16th Elysian Drop Troops
 * Epsilonian Guard
 * Erawan Freelancers
 * Erland 22nd Motorized
 * Falterravan Armoured
 * 584th Firestarters
 * Fists of Chonlhan
 * XXI Flotte Coloniale
 * Forax 206th Binary Mobile Intantry
 * Framlingham Rifles
 * Frumunda 23rd Armoured Infantry
 * 13th Garlatan Drop Legion
 * Garnthe 7th Armoured Cavalry Regiment
 * Glavian Skirmishers 17th
 * 14th Gleastonian Rifles
 * Golokov 3rd Armoured Cavalry
 * Gracian 1st
 * 19th Grey Lancers
 * 4th Grey Phantoms
 * Grinnuth 27th
 * Guardia 4th
 * 43rd Gudrunite Rifles
 * Hadley's Hope XI Rifle Regiment
 * 137th Hadris Rift
 * 43rd/65th Heidrun
 * 425th Heliothrix Combine
 * 1st Heronian Battle Group
 * XII Holding Regiment
 * Hussaria 41st Armoured
 * Hyperion Guard
 * 6th Hyrkan Regiment
 * Iberian 1st
 * Iionian 9th Dragoons
 * Ionis XXII
 * 12th Imbrium Dragoons
 * Iron Tower Regiment
 * Irridian XIV Ironlords
 * Ishan 5th
 * Istanian 3rd Infantry
 * Ivlordian 16th
 * Janus 1st
 * Janus Xll Garrison Force
 * Jarhardy Shock
 * Jopall Indentured 114th Rifles
 * Jopall Indentured 17th
 * Jyhaddic 9th
 * Kalevala 15th
 * Kandorian 8192nd Light Infantry
 * Karis 12th
 * Katakurika First
 * Kaylen Lancers
 * Keldian Light Infantry
 * Keltaxan 113th
 * Khorporovka 3rd Crusade Army
 * Khumium Militia
 * Khymer 14th
 * Kiridian 5th
 * Knovian Gharkas 14th Company
 * Kortoth
 * Kreigars 3rd
 * Kruegers Reapers
 * 51st Kynskite Dragoons
 * Kyshakkian 21st Penal Legion
 * 32nd Lanthan Drop Troops
 * 14th Lieran Rifles
 * 282nd Light Colonial Guard
 * 93rd Lost Hope
 * 31st Lucian
 * Lunari 23rd Orbital Strike Group
 * Macharian 24th
 * Madeus 3rd
 * 14th Mandalay
 * 1st Maninninan Rangers
 * Mercutian 141st Armoured
 * 12th Methuselan Infantry (Mechanised)
 * 3rd Mirra Nomads
 * Miskolc Prime City Rats
 * Mistian 213th Para-Troops
 * 1st Molovian Guard
 * 303rd Mordant Acid-Dogs
 * 667th Mordian
 * 113th Mordian
 * 23rd Mordian
 * 10th Mordian
 * 7th Mordian
 * Morloc 404th
 * Mortimer IV
 * Mulsarian VII Army
 * 13th Munisipice Fusiliers
 * Mycenean 1st Off-World
 * 42nd Mykran Rifles
 * Nebian 3rd
 * Necromunda 8th Infantry
 * New Crobuzon Militia
 * New Phraxian 42nd
 * Nimbus 2nd
 * Noctus 4th
 * Nomulan Wolves
 * Octavis 3rd
 * Orthos XIIth
 * 194. Parsus III
 * Patrian 121st Light Infantry
 * Patrol Group Aquila
 * Peraxxian 101st "Dawn Breakers"
 * Pheonix 49th
 * 13th Pinolus V Task Force
 * XVI Phobos 
 * Phrygian 32nd
 * Phyrgian III
 * 23rd Phyruss Rifles
 * Phyruss 81st Regiment
 * Phyrussian 10th
 * Polaron Delence Force
 * Polisian 43rd
 * 303rd Praetorian
 * 35th Praetorian
 * 13th Praetorian
 * 5th Praetorian
 * Pyotorgors 292nd Arctic Rifles
 * Rantaran 6
 * Rardonian 104th
 * Razacks Roughnecks
 * Reconnaissance Regiment
 * 73rd Rescue Fleet
 * 1st Rigan Rifles (Mechanised)
 * Rimini 54th
 * 12th Ritzos
 * Royal Hernovan Grenadiers
 * Royal Volpone 50th "Bluebloods"
 * Royal Volpone 23rd
 * Rygarian 8th Army
 * Saharrian XLV
 * Seced 13th
 * 1st Sempernox
 * Serennian Irregulars
 * Sidoneon 95th
 * Silar VII Sentinel Company
 * 25th Skarran Guard
 * Solus 13th
 * 21st Sonnen Guard
 * Sons of Mjolnir
 * Soran 8th Regiment
 * Sphynxium Diamonds
 * Strike Force Antares
 * Strike Force Crimson
 * Strike Force Belarius
 * 13th Studka Rifles
 * 352nd Sturm Pioneers
 * Supremacy Force Marchon
 * Talasan 1st
 * Tallarn Desert Raiders 506th
 * Tanner IV 26th Regiment
 * Tantris 1st
 * Tarentum XXVII
 * Task Force Perdius
 * Task Force Damocles
 * Telluride 39th Armoured Battle Group
 * 1st Terratus Strike Regiment
 * Teryaskian Red Guard
 * The Raiders of Ar Rustaq
 * 290th Thracian
 * 1st Thunderers
 * Torlean Armoured Guards
 * Tralian 4th
 * Tturas 18th "Orphans"
 * 122nd Tuigan Marksmen
 * Turian 264th Regulars
 * Ulantii XIV
 * Uriah 501st
 * 1st Uthman
 * Utican IV Desert Foxes
 * 48th Valdian Rifles
 * 451st Valhalla
 * 301st Valhalla
 * 7th Valhalla
 * 5th Valhalla
 * Vandeen Guard 9th
 * Vandorian 23rd
 * Vannheim 8th
 * Vanth Defence Legion
 * Varseen 71st Enclave Heavy Drop-Legion
 * Vastadt 71st
 * Vastadtian 32nd
 * Vednikan 47th Rifles
 * Victarian XXXI Tank Regiment
 * Vitrian 43rd
 * Vittorrian XVII
 * Vittrian Dragoons
 * Volcanica 1st
 * 187th Wahation Guard
 * Weylond 71st Fusiliers
 * 181st Wolfpack
 * 5th Yamin
 * Yontisgrod Volunteers
 * Zantinian 3rd Infantry Regiment

Ordo Malleus

 * Inquisitorial Task Forces - CLASSIFIED
 * Grey Knights - CLASSIFIED
 * Inquisitorial Storm Troopers
 * Nemesis Tesera - estimated 38 Companies
 * Ocularis Terribus War Zone - CLASSIFIED

Departmento Munitorum

 * Engineer Corps - 18
 * Siege Auxilia Corps - 28 Counter-siege batteries

Officio Assassinorum

 * Agents - CLASSIFIED

Templars Psykologis

 * Disruption Squads - 37
 * Augur Teams - 6

Battlefleets

 * Battlefleet Cadia - 12 Battleships, 12 Cruiser Squadrons, 21 Escort Squadrons
 * Battlefleet Corona - 7 Battleships, 13 Cruiser Squadrons, 17 Escort Squadrons
 * Battlefleet Gothic
 * Battlefleet Scarus - 5 Battleships, 9 Cruiser Squadrons, 13 Escort Squadrons
 * Battlefleet Solar
 * Battlegroup Nemesis
 * Battle Group Imperatis
 * Bakka Sector Task Force

Vessels of Note

 * Galathamor (Emperor-class Battleship) - Admiral Quarren's flagship.
 * Honour & Duty (Emperor-class Battleship)
 * Duke Lurstophan (Dauntless-class Light Cruiser)
 * Abridal's Glory (Gothic-class Cruiser)

Estimated Fleet Assets

 * Front Line Battle Groups - 21
 * Rear Echelon Battle Groups - 36
 * Independent Strike Groups - 4
 * Space Marine Battle-Barges - estimated 21+
 * Space Marine Strike Cruisers - estimated 150+
 * Space Marine Escort Squadrons - estimated 200+

Collegia Titanica

 * Legio Astorum - Entire Legion
 * Legio Gryphonicus - Entire Legion
 * Legio Ignatum - Entire Legion
 * Legio Metalica - Demi-Legion
 * Ordo Reductor - Demi-Legion
 * Divisio Telepathica Psi-Titans - CLASSIFIED

Knights

 * House Arokon - 4 Households of Knights
 * House Krast - 2 Households of Knights
 * House Lakar

Other Mechanicus Assets

 * Centurio Ordinatus - 4 Ordinatus
 * Skitarii - 87 Regiments

Senior Command

 * Abaddon the Despoiler - Warmaster of Chaos and overall commander of the Forces of Chaos
 * Typhus - Herald of Nurgle, and Plague Fleet commander.
 * Kossolax the Foresworn - Chaos Lord of the Foresworn Renegade Chaos Space Marines warband and fleet commander.

Chaos Space Marine Legions

 * Alpha Legion - 20+ unconfirmed sightings in all sectors
 * Black Legion - Major presence in all sectors
 * Death Guard - Major presence in Subiaco Diablo
 * Emperor's Children - Unconfirmed actions against Eldar reported
 * Iron Warriors - Suspected presence in the Cadian System
 * Night Lords - Unconfirmed reports of presence in all sectors
 * Thousand Sons - Active in the Caliban and Prospero Sectors
 * Word Bearers - Active in rear echelon sectors
 * World Eaters - Significant involvement in all sectors

Renegade Chaos Space Marine Warbands

 * Extinction Angels
 * The Pyre
 * Sons of Malice
 * Violators - 3 confirmed actions in Cadia Sector
 * Warp Ghosts - Unconfirmed sighting in Agripnaa System

Major Traitor Guard Units

 * 5th Columnus - Presence confirmed - Belis Corona
 * 666th Regiment of Foot - Confirmed presence - Cadia
 * Discilan Apostates - Unconfirmed
 * Haradni 13th
 * Jenen Ironclads - Major presence - Kromat System
 * Sentrek Freemen
 * The Traitor 9th - Significant presence - Kantrael System
 * Ubridius Light Infantry - Major presence - Cadian Sector
 * Volscani Cataphracts - Active - Cadia

Estimated Mutant Hordes

 * The Anointed of Aq'si - 6 attacks confirmed - Belisar System
 * The Shyis'slaa - Linked to cult uprisings - Albitern System
 * The Stigmatus Convenant - Significant presence - Mackan System
 * The Unsanctified - Unconfirmed involvement - Bar-el System

Traitor Titan Legions

 * Death Stalkers - Unconfirmed involvement on Cadia
 * Fire Masters - Limited presence in Cadian Sector
 * Iron Skulls - Major force sighted on Vorga Torq
 * Legio Mortis - Major presence confirmed on Cadia
 * Legio Vulcanum I - 4 unconfirmed assaults on Belisar and Kromat
 * Legio Vulcanum II - Suspected presence on Subiaco Diablo

Battlefleets

 * The Grand Fleet of Abaddon the Despoiler - 7 Battleships, 13 Heavy Cruisers, est. 23 Cruiser Squadrons, est. 30 Escort Squadrons
 * The Grand Fleet of Kossolax the Foresworn - 1 Battleship, 3 Cruiser Squadrons, 8 Escort Squadrons
 * The Plague Fleet of Typhus - Terminus Est, 2 Battleships, 3 Heavy Cruisers, 5 Cruiser Squadrons, est. 12 Escort Squadrons

Notable Vessels

 * Plagueclaw (Unknown Class Capital Vessel)
 * Darkblood (Styx-class Heavy Cruiser)
 * Planet Killer (Undesignated Class Capital Vessel)
 * Merciless Death (Despoiler-class Battleship)
 * Fortress of Agony (Despoiler-class Battleship)

Fleet Assets

 * Battlefleets - est. 38
 * Blackstone Fortresses - 2
 * "Wolf Pack" Squadrons - est. 19