13th Black Crusade (Original)

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 and resulted in a minor victory for the Forces of Chaos and gave the Warmaster Abaddon 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 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
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, 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 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 years after the first Chaos raid on the Imperial listening post at Arx, in 142.M41, the forces of Abaddon the Despoiler, 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 Chaotic warfleets struck at a dozen Imperial bases and sent the warships of the Imperial Navy's Battlefleet Gothic reeling. Chaos starships attacked all across the Gothic Sector and the first inkling of Abaddon's true intentions in launching the Twelfth 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 hoorifying use of the captured base's advanced alien technology.

Abaddon's fleet possessed a devastating weapon, never before sen 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 Mechanicum builders, but was a well-deserved epithet as Abaddon demonstrated at the Cardinal World of Savaven. The account of the utter destruction of Savaen 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 with 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 fleet's crusade. At the beginning of 151.M41, Lord Admiral 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 destabilized 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 Thirteenth 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 Obscuras. All were converging on the core star systems of each sub-sector and while this number of Space Hulks was rare, it was not exceptional. System defence ships scrambled to intercept them and prevent them from reaching their star systems' inhabited worlds. The vessels of the Adeptus Astartes boarded those they could, but their numbers were limited, as always. The Space Marines found them to be Chaos-twisted and disease-ridden nightmares, encrusted with all manner of necrotic matter and toxic filth. Subsequently, every such vessel encountered was destroyed with plasma 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 Imperial Navy 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 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 himself. 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 fleet'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 diseases, just as they had before 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 around the Eye of Terror. The continued health of these fanatics 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 scorres 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 as the newest province in the Plague Lord's eternal kingdom of death.

Outcome
UNDER CONSTRUCTION

The Forces of Chaos won a small if significant victory over the Imperium and the Eldar and captured 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 belongs to Chaos (Imperial forces forced to retreat to the smallest continent). The battle for Cadia will last centuries without aid... but if Chaos can gain headway in the space above Cadia, then the defenders will be doomed - especially with the Blackstone still there. Even without space aid, there's a large chance that simple supplies such as food will be unable to reach the defenders, and that the defenders will starve to death.

A new Daemon World exists, and it has taken the place of the planet Ulthor. It is now a gateway for vile forces of Chaos, acting as a beacon to daemons of Nurgle - the Chaos God whose forces now own the planet. It is possible that whole Chaos armies will be able to emerge from this world, and the terror this could bring to the rest of the Imperium is unfathomable. The campaign was not without its victories for the defenders, however. For although Belis Corona - the location of the greatest shipyard of the Imperium - is now heavily infested with myriad Tyranid organisms, the shipyards remain functional - albeit at a fraction of their normal capacity, such is their sheer size. Also, the ruins of their ancient shattered Chapter homeworld of Calibanhave been recaptured by the Dark Angels. Who can say what relics they've re-acquired? The Orks, however, have taken a huge portion of Scarus Sector -- and the chances are good that the rest of the sector will also fall to the Greenskins. On the former Forge Worlds of this sector, hundreds of Gargants are starting to take form as the Mekboyz race to complete their deadly god of a machine first. There are even rumours that this is spurring Mekboyz the galaxy over to begin construction of their own Gargants, and that this will cumulate in a Waa-Ork! Every thousand years, a massive collection of Waaghs begin and carve out new Ork empires, destroying hundreds of planets and enslaving hundreds more - and they all begin with a massive beginning of huge numbers of Gargants.

As for Eldrad Ulthran... the bravest and most noble leader of the Eldar since before the coming of She Who Thirsts, has perished. In a last-ditch effort to stop the Black Stone Fortress from crushing the defenders of Cadia and save the soul of the Fortress, he and a select few Warlocks teleported aboard. Within minutes all the Warlocks were drained of life by the Fortress's bottomless thirst, and when Eldrad reached out to try to touch the Eldar spirit at the core, he found only the actual power of Slannesh - her greatest daemon - and Eldrad's soul was sucked in and consumed. The Chaos Victory at Cadia has just seen a new, and even more bleak time for the Imperium, when their power could collapse, and savage fighting amongst all races of the galaxy erupts!

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.

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 Fen Guard -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

 * '79th 'Britan Armoured
 * 3rd Cadian 
 * 9th Armoured Cadian 
 * 107th Cadian 
 * XII Catachan 
 * 23rd Death Korps of Krieg
 * 9th Dernhelm
 * 153rd Desert Devils
 * 41st Elysian Drop Troops, "Angel Guard"
 * XXI Flotte Coloniale 
 * Framlingham Rifles
 * Hadleys Hope XI Rifle Regiment
 * 43rd/65th Heidrun
 * 6th Hyrkan Regiment
 * 12th Methuselan Infantry (Mechanised)
 * 303rd Mordant, "Acid Dogs"
 * 10th Mordian
 * 8th Necromunda Infantry
 * XV Phobos 
 * 5th Praetorian 
 * 35th Praetorian 
 * 12th Ritzos 
 * 290th Thracian 
 * Reconnaissance Regiment
 * 352nd Sturm Pioneers
 * 54th Valhalla 

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

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

Estimated Fleet Assets

 * Front Line Battle Groups - 21
 * Rear Echelon Battle Groups - 36
 * Independent Strike Groups - 4
 * Space Marine Battle-Barges - est. 21+
 * Space Marine Strike Cruisers - est. 150+
 * Space Marine Escort Squadrons - est. 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-all sectors
 * Black Legion - Major presence - all sectors
 * Death Guard - Major presence - Subiaco Diablo
 * Emperor's Children - Unconfirmed actions against Eldar reported
 * Iron Warriors - Suspected presence - Cadian System
 * Night Lords - Unconfirmed reports - all sectors
 * Thousand Sons - Active - Caliban and Prospero Sectors
 * Word Bearers - Active - rear echelon sectors
 * World Eaters - Significant involvement - all sectors

Renegade Chaos Space Marine Warbands

 * Extinction Angels
 * The Pyre
 * Sons of Malice
 * Violators - 3 confirmed actions - Cadia Sector
 * Warp Ghosts - Unconfirmed sighting - 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 Legio Titanicus

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