M31

''Historian's Note: All dates relating to the Great Crusade and the Horus Heresy are only approximations. Imperial records from this time are too fragmentary to be wholly reliable.''
 * c. 001.M31 Aghoru Campaign - The Imperial Compliance of the world of Aghoru (officially codified in Imperial records as 28-16) was an action carried out by units of the Thousand Sons Legion that was achieved through diplomacy and was considered a success; secondary combat occurred against apparent Warp denizen infestation (beings known to the local population as "Elohim") within the subterranean passages of a titanic peak that stood taller than Olympus Mons on Mars. The Thousand Sons' forces were enhanced by a small unit drawn from the Space Wolves Legion during this operation.
 * c. 001.M31 Ark Reach Cluster - The Ark Reach Cluster had been discovered by the Word Bearers Legion's 47th Expeditionary Fleet; it was a group of binary stars occupied by a number of belligerent planetary empires that rejected the Imperium's offer to become part of the Emperor's growing demesne. This Imperial Compliance action of the Great Crusade was carried out through the combined efforts of the Thousand Sons working in concert with elements from the Space Wolves and the Word Bearers Legions. The first four star systems fell to the Word Bearers and Space Wolves. But the fifth and sixth world, known as Shrike, required the assistance of the Thousand Sons. The return to the XV Legion of the dreaded mutational "flesh-change" occurred at the conclusion of this campaign and helped to bring on the eternal enmity between the Space Wolves and the Thousand Sons whom regarded their cousins as "impure."
 * c. 001.M31 Kayvas Persecution – Many tribes of Orks, scattered and leaderless after the hammerblow they had suffered at Ullanor during the Ullanor Crusade, had fled to the points of the etheric compass – and many had come to rest in the Kayvas Belt, where they carved new outposts out of the drifting, mineral-rich rocks, licked their wounds while they re-armed. The Greenskin xenos soon began to strike out at nearby Imperial star systems and newly Compliant daughter colonies, and it was the duty of the Space Marine Legions to reinforce the lesson of Ullanor again. The Alpha Legion had tracked them to their lair and petitioned the Warmaster Horus for the reinforcements required to prosecute their plan of annihilation, but after the war at the world called Murder and the disastrous engagement with the civilisation known as the Interex, the Luna Wolves had been reluctant to commit ships to Alpharius’ new campaign. In the end, it was the Blood Angels who agreed to assist their cousins in the XX Legion, with Sanguinius himself marshalling a sizable intervention to support the efforts of the 88th Expeditionary Fleet. The mission, Alpharius said, would be five standard years in execution. The Angel rejected that premise and promised it would be over in one, and he committed vessels from every active Blood Angels expeditionary fleet to the cause. Sanguinius was proved right -- more or less. Just over thirteen months after the commencement of the Kayvas initiative, the Orks were almost totally annihilated, but like animals backed into a corner they fought harder than they ever had before. The 88th Expeditionary Fleet took their warships into the Kayvas Belt and vanished from the sensors of the IX Legion's fleet, leaving the Blood Angels flotilla at the edge of the system to wait. Soon it became clear that the mission Alpharius had been so eager to secure support for was little more than picket duty. First one at a time, then in squadrons and finally in fleets, the Orks began to flee from the Kayvas System. Each time they bolted for open space beyond the mass shadow of the supergiant sun and its asteroid belt, the Blood Angels were waiting for them. Imperial starships and Ork cruisers engaged in deadly games of cat-and-mouse that lasted for weeks on end, threading in and out of the dense dust clouds at the periphery of the star system, mercilessly hunting each other. Mighty vessels clashed again and again, but months of protracted ship-to-ship engagements and naval warfare made the Sons of Baal restless. They had been bred for battles where they could face their foes, not ranged conflicts conducted over huge spans of empty vacuum. However, the chance to fight blade-to-blade did come. The behaviour patterns of the Ork crews began to change. They eschewed what little animal cunning they had and made mistakes. Instead of showing the brutish slyness they were known for, the xenos exhibited conduct that more closely resembled panic. They would take chances, running the gauntlet of the Blood Angels' blockade when the odds were stacked against them. It was almost as if there were something at their backs that they feared far more than the guns of Sanguinius’ Legion. No one within the IX Legion knew what the Alpha Legion had done to make the Orks run. All that was certain was that the Alpha Legion had gone dark, only rising to send regular communiqués out to the Blood Angels' blockade fleet that contained little more than a message to "maintain the line." Finally, Sanguinius tired of Alpharius' evasive manner and sent a frigate in past the outer marker, in defiance of the rules of engagement the two Legions had agreed upon. When the frigate returned weeks later, the crew reported that they had come across no signs of their allies, only the wrecks of Ork vessels and the bodies of dead aliens. The Alpha Legion's 88th Expeditionary Fleet comprised hundreds of warships, and yet no trace of them was sighted. The tempo of the Kayvas campaign had finally reached a terminal pitch. The final remnants of the Ork forces took flight from the belt in a disordered exodus, and perished in the flashes of Lance cannons and torpedo barrages as they crossed the sentry line. At last, the Alpha Legion's starships appeared at the very edge of scanning range, apparently moving in a wall, herding the enemy towards the fringes of the system. The Alpha Legion stated they had fully exterminated the alien infestation in the Kayvas Belt, and were grateful to the Blood Angels for their co-operation. The blockade was finally over, and with the death of the final monolithic Ork wreck at the hands of the Blood Angels fleet, the campaign came to a successful conclusion, though relations between the IX and XX Legions remained somewhat strained.
 * c. 001.M31 Assault on Nurth - The Desert World of Nurth was discovered during the Great Crusade by the 670th Expeditionary Fleet under the command of Lord Commander Teng Namitjira. Nurth was a lost human colony world. The population refused to accept the light of the Imperial Truth and opted not to join the Imperium of Man, resulting in a drawn-out, protracted compliance campaign that would eventually result in the death of the entire world. The Primarch Alpharius and a force from his XX Legion, the Alpha Legion, fought alongside the 670th Expedition during the tragic campaign to bring the world of Nurth to Imperial Compliance, but never became an official part of the 670th Expedition's order of battle. Lord Commander Namitjira remained in formal command during the operation, though of course he deferred to the Primarch's orders. When first contacted by the Imperium, Nurth was a primitive, pre-industrial Desert World with geographic features fairly typical for such an arid environment. An exception to this was the harbour of Mon Lo, in the city of the same name. The harbour, while appearing perfectly natural to the ordinary onlooker, was actually an entirely artificial construction, having been created by the xenos organisation known as the Cabal some 11,826 Terran years before the arrival of Imperial forces on the world. Before natural environmental changes had filled the harbour of Mon Lo with water, the bay had served as a giant landing pad or "waystation" for the Cabal's massive primary starship. As such, a detailed orbital scan of Mon Lo revealed features similar to that found on other worlds where Cabal waystations were built and the Cabal's mobile headquarters had come to rest for a time. Another location that featured unusual terrain was the town of Tel Khat, also known as Visages. The plain surrounding the town was littered with old, weathered sculptures of human heads, made from diorite and ranging in size from a pebble to a boulder. For unknown reasons, the ground of Nurth was coloured a striking combination of red and orange and the sky an unusually vibrant blue. This, combined with the brightness of the desert environment, meant that glare-protection was essential equipment for all military forces operating on the planet, so as to avoid disorientation and eventual eye damage. Nurth was eventually destroyed by the Nurthene themselves, as, on the verge of losing the war against the Imperial forces, the Echvehnurth, the Chaos-corrupted Nurthene military forces, activated a Chaotic weapon known as a Black Cube, an ancient weapon of planetary destruction created eons before by the first intelligent races of the galaxy. This weapon, through unknown means, transformed the climate of the planet, turning the air into noxious vapours utterly inimical to any form of life, and generating winds so strong that they scoured soil from the bedrock and raised the temperature to the point where the ocean boiled. In a matter of days, the process was complete, leaving Nurth a lifeless Dead World.
 * c. 001.M31 Compliance of Caldera - This was an unusual campaign of the Great Crusade that involved bringing the world of 154-4, known as Ibsen by its inhabitants, into Imperial Compliance. The Salamanders Legion, lead by the Primarch Vulkan, were joined by the Death Guard and the Iron Hands Legions, both lead by their own respective Primarchs. The world was undeveloped, and largely inhospitable to human life, but possessed valuable mineral deposits. However, the Imperial forces faced stiff resistance for control of the planet from the Eldar, who had placed a garrison upon Ibsen. The Eldar forces—including Seers, Warlocks and other combat Psykers -- could not have expected to defeat one Legion of Astartes, let alone three. The mystery deepened when the semi-feral, primitive human tribes inhabiting the planet seemed more sympathetic to the Eldar, or at the very least, not welcoming to their human liberators. The Salamanders and other Imperials defeated the Eldar relatively easily as expected. After the conquest, the Salamanders learned that the Eldar had been defending a network of menhirs which served as psychic nodes and that fed into a giant arch, where the final and most brutal confrontation between the Astartes and the xenos had taken place. The arch itself had been located thanks to a mysterious Remembrancer attached to the Salamanders, with whom Vulkan had had an unsettling conversation before the battle. After the slaughter ended, Vulkan saw the Remembrancer loitering by the arch and then suddenly disappearing. Following him, Vulkan and his elite Pyre Guard descended into the chambers beneath it, through a portal at its base. There they found a crude warding ceremony taking place, conducted by the primitive human tribal priests, who were ready to sacrifice an ancient Dark Eldar witch. Finally, Vulkan realised the truth: the arch was in reality a Webway portal (though none of the Imperials, including Vulkan, knew this at the time); Vulkan had seen a "gate" like this before, in his Nocturnean youth, when Dark Eldar repeatedly utilised such a portal to raid and pillage the planet. The Eldar had taken control of the portal by defeating their dark cousins, and in the process had freed the indigenous human population of Ibsen from the horrors of Dark Eldar raids; the Eldar had been seen by the native humans as liberators. Terrified by the defeat of their liberators at the hands of the Imperium, the natives had sought to sacrifice their Dark Eldar captive to ward off the inevitable return of her race; the mysterious "Remembrancer" who was nowhere to be seen had actually been the Emperor in disguise, who must have had a great interest in the particulars of this mission since he had ordered so many resources committed to it. Vulkan ordered Ibsen and its irredeemably corrupted population cleansed by flame. He renamed the scoured, Nocturne-like Dead World that remained Caldera. The world was now ready to receive new human colonists and to be exploited for the benefit of the Imperium.
 * c. 002.M31 Compliance of Melchior – The Imperial Compliance of Melchior was a joint campaign that was carried out by both the XVI Legion and the Blood Angels Legion. The world was the last bastion of the xenos known as the Nephilim -- hulking entities of roughly humanoid shape who were smooth like carvings of soapstone, with abstract shapes approximating arms and legs. Their dome heads emerged from their shoulders without a neck, and an array of olfactory slits and eye-spots ringed the surface of their skulls. In the light, the Nephilim looked like objects crafted of blown glass, their semi-transparent flesh glowing in the bright day. The Nephilim possessed an unhurried, careful agility like that of sea-going creatures seen through the walls of a glass tank. They moved deceptively slowly through air as if they were swimming in water, but they could move fast if they wished, darting and spinning, becoming difficult to hit. The alien giants, mocking humanity’s great dream of peace and unity, had left a trail of destruction behind them that had claimed a hundred worlds before they had come to rest upon Melchior. Sagan, the DeCora Spine, Orpheo Minoris, Beta Rigel II; each of these planets had been denuded of all Human life, populations herded into empath-chapels as big as mountains and then slowly consumed. Even their name, Nephilim, the name of the fallen seraphs, was a name taken from ancient human mythology -- that of Terra, Caliban and Barac. The true horror of it was that the Nephilim used those they preyed upon to do their soldiering for them, snaring the pliant, the lonely, the sorrowful with their ideal of an attainable godhood. They plied their victims with stories of eternal existence for the faithful, of endless sorrow for the agnostic; and they were very good at it. Perhaps the xenos really believed that what they were doing was somehow taking their victims closer to a form beyond flesh, to an afterlife in an eternal heaven-state; it did not matter. With their advanced technology they implanted bits of themselves into their thralls to further their communion. They cut their own flesh and made living masks to mark their devotees. The Nephilim controlled minds, either through the transmitted power of their will or through the weak character of those they chose. They were an affront to the Emperor's hope for the creation of the rationalist, secular galaxy outlined by the Imperial Truth. They represented not only an offence to the purity of a precious human ideal but in their insidious cuckoo-nest displacement of those who foolishly gave them fealty. For what the aliens fed upon, what the Scout Marines of the Blood Angels and Luna Wolves had seen and reported back, were the very lives of those who cherished them. The empty chapels were piled high with stacks of desiccated corpses, bodies that had been aged years in only hours as all living essence was siphoned from them. The Primarchs of the Legions were disgusted as the true understanding of the enemy they faced was revealed. The Nephilim fed on adulation. In the strategium of his flagship, the Vengeful Spirit, the Horus showed his brother Sanguinius, the Primarch of the Blood Angels, the plan that he had conceived to break the will of the Nephilim. Horus wanted the Blood Angels to march shoulder-to-shoulder with their cousins, cowing the aliens with the sight of an army of thousands of powerful Astartes rolling without pause to the gates of their last bastion. And then through those gates, over the battlements, not stopping, not pausing to parley or hesitate. "Like the ocean these things sprang from," Horus had said, "we will roll over the aliens, drag them down and drown them." The sheer bombast of the plan was its greatest strength, but Sanguinius had not been easily swayed to it. This blunt, brute-force approach was better suited to their more intemperate brother Primarchs, to Leman Russ or to Angron. Sanguinius felt that neither he nor Horus were so artless, so focused upon the target to the detriment of all else, but in the end he agreed. When the time came to enact their audacious plan, Horus and his Luna Wolves met the xenos army on the sparkling white plains of the Silver Desert. Before open hostilities began, Horus attempted to parlay with the Nephilim one final time, but the overconfident xenos refused to capitulate, casually informing the humans that they could not win. Horus informed the xenos commander that it had made a grave error, for it would be the Nephilim who would fall. The Luna Wolves would be the anvil upon which the xenos would break, and the Blood Angels would be the hammer. With lightning speed, the heavens screamed as a rain of ceramite Drop Pods tore through the outer atmosphere of Melchior and fell like flaming meteors towards the Silver Desert. Falling with them were Stormbird and Thunderhawk assault gunships that turned and wheeled through the air towards the gargantuan Nephilim encampment, carrying company upon company of the IX Legion. The speed of their assault was the key to victory; the alien invaders and their zealots had successfully been drawn out to confront the massed forces of the Luna Wolves, leaving the defences on their flanks thinned and permeable. But the xenos giants were not slow in their thinking, and the moment they understood that they had been duped, they would attempt to regroup and fortify. The Blood Angels did not allow that to happen. The Nephilim were broken and cut down, their cohesion shattered by the brutal deep strike. Caught between the brutal fury of two Space Marine Legions on Melchior's shining sands, the Nephilim were finally put to the sword.
 * c. 002.M31 Preaixor Campaign - This was an Imperial Compliance campaign that was jointly carried out by the Death Guard and the Emperor's Children Legions. During this campaign, Captain Saul Tarvitz of the Emperor's Children earned Death Guard Battle-Captain Nathaniel Garro's amity, proving to him that for all the reputation of Fulgrim's Astartes as overconfident peacocks, there were still men amongst the ranks of the III Legion that embodied the ideals of the Imperium. The two became Honour Brothers, carving a small eagle on each others vambrace by knifepoint, a sign of the battle debt they owed one another. When they clasped each others' vambraces in a warrior's handshake, the two eagles joined together to form the Imperial Aquila.
 * c. 002.M31 Ullanor Crusade - The Ullanor Crusade was a vast Imperial assault on the Ork empire of the Overlord Urrlak Urruk during the Great Crusade of the early 31st Millennium. The capital world of this empire, and the site of the final assault, lay in the Ullanor System of the Ullanor Sector, which had long been under the dominion of Urrlak Urruk's Greenskin pocket empire. The Crusade included the deployment of 100,000 Space Marines, 8,000,000 Imperial Army troops, and thousands of Imperial starships and their support personnel. The Luna Wolves spearheaded the assault into the heart of Urlakk's fortress-palace. During the height of the assault, Horus and a retinue of Luna Wolves Terminators from the elite 1st Company came face to face with the massive Ork Warlord and a retinue of 40 Ork Nobs. Horus charged into the Nobs, hacking them apart with his Lightning Claws until he finally faced the Ork Overlord himself. Urlakk was simply no match for the Primarch's skill and unnatural power. First crippling his enemy, Horus hefted Urlakk's broken body out onto the roof of the Greenskin's palace and threw it screaming from the battlements to fall far below amongst the horde of Orks still assaulting the lower levels. Seeing their leader defeated sent a panic through the Greenskin forces, which started to fall back from the Terminators. But the fleeing mobs found they had nowhere to run, as the outer walls had been breached by the attacking Luna Wolves, and the day turned into a slaughter. In the Overlord's chamber, Horus found every Ork and Terminator dead, apart from the gore-drenched First Captain of the 1st Company, Ezekyle Abaddon, who was surrounded by crushed and Ork bodies. The Ullanor Crusade marked the high point of the Great Crusade's vast effort to reunite the scattered colony worlds of humanity. The Orks of Ullanor represented the largest concentration of Orks ever defeated by the military forces of the Imperium of Man before the Third War for Armageddon began during the late 41st Millennium. Following the defeat of the Orks of Ullanor, the Emperor of Mankind returned to Terra to begin work on his vast project to open up the Eldar Webway for Mankind's use. In his place to command the vast forces of the Great Crusade he left Horus. Horus was raised to the rank of Imperial Warmaster and given command authority over all of his fellow Primarchs and every Expeditionary Fleet of the Great Crusade. But the Primarchs never came to terms with the Emperor's absence. Their hurt feelings over his seeming abandonment of the Great Crusade to pursue a secret project whose purpose he chose not to reveal to his sons laid the seeds of corruption that would ultimately blossom into the Horus Heresy. Yet the Emperor sent word from Terra that in honour of the great victory at Ullanor, the Luna Wolves should henceforth be known as the Sons of Horus, in honour of their Primarch's singular deeds, though Horus, with typical humility, chose not to rename his Legion at this time.
 * c. 002.M31 Compliance of One-Five-Four-Four - Shortly after the Emperor quit the Great Crusade following the triumph of the Ullanor Crusade, the Iron Hands Legion took part in a joint pacification of the Eldar-controlled world designated One-Five-Four-Four alongside the Death Guard and Salamanders Legions. Charged with bringing the desert regions of the planet into Imperial Compliance, the campaign did not bode well for the Imperial forces as they were hindered by the inhospitable terrain and the fluid battle tactics of the xenos that took a savage toll on Ferrus Manus' forces, placing him well behind schedule in purging the world. The Primarch was especially troubled by the weakness and infirmity that seemed to surround him, especially in regards to the Imperial Army forces that could not seem to overcome the harsh desert conditions of the cursed planet, proving the Iron Hands mantra that "the flesh is weak." Determined not to lose face in front of his brother Primarchs Mortarion of the Death Guard and Vulkan of the Salamanders, Ferrus decided to abandon the Imperial Army regiments if they were unable to keep up with his Space Marines. The Primarch sent of his sons, Bion Henricos, to liaise with the regiment's colonel, and informed him of the Primarch's intentions. Henricos felt a surprising twinge of remorse as he did so. Meanwhile, for reasons the Primarch could not explain, he was continuously troubled by disturbing dreams. He was also disturbed by the possibility that Eldar witchcraft might be causing his Astartes to under perform. The Primarch confessed as much to his First Captain Gabriel Santor, but he did not reveal his personal feelings that the sooner the campaign came to a successful conclusion and the X Legion left the benighted planet, the better that he would feel. Unbeknownst to Ferrus Manus, two Eldar discussed his fate. One of them decided to intervene, to ensure that Ferrus Manus walked along the more positive of the two possible paths leading to his future. The other Eldar warned against such interference, warning his companion that "Stone cannot bend, it can only break." The Iron Hands pushed on into the deep desert and arrived at a suspicious valley. For reasons that he cannot explain, the Primarch felt that this area was important somehow, but he was loath to investigate it further without a Scout force. His Legion currently lacked this important resource, and so, Brother Henricos suggested to the Primarch that it would be beneficial if they awaited the arrival of the errant Imperial Army forces. They possessed the necessary units to perform such a mission, and by using their scouts in such a way, this would help make the regiment feel that they were playing a valued role in the current campaign. But unfortunately, Henricos' suggestions were disregarded by his superiors. Unwilling to wait any longer, the Primarch ordered the Iron Hands to descend into the valley. As soon as the bulk of their forces reached the floor of the valley, a mysterious darkness engulfed them, followed by severe inclement weather. Eldar warriors lay in wait and quickly ambushed the disoriented Mon-keigh warriors in close-quarters battle. They also employed a mysterious weapon that overrode the Iron Hands' Bionics, blinding those with bionic eyes and overriding and controlling bionic hands that turned their weapons upon their fellow Battle-Brothers or themselves. The Iron Hands assault force was only saved by the timely arrival of Bion Henricos' rearguard force, who took out the Eldar Warlocks responsible for the malefic psychic attack. The Eldar were forced to retreat, leaving the Iron Hands to recover. But things soon took a drastic turn when it was noticed that Ferrus Manus was missing. Ferrus found himself within a cavern and where he was assaulted by a barrage of prescient visions and perceptions of death—of his Legion, his Astartes and even himself. He also saw metaphorical representations of his fellow Primarch brothers and was perplexed by feelings of betrayal that were engendered when he gazed upon a statue of his closest brother Fulgrim. During this entire ordeal, Ferrus felt as if he was being pursued by a malevolent serpentine entity. Irritated by such sorcerous parlour tricks, the Primarch pressed onward and explored the caverns further. Meanwhile, First Captain Santor detailed 50 Morlock Terminators to help assist him in his search for the X Legion's missing Primarch, and he assigned command of the Legion to Shadrak Meduson to continue on with the Iron Hands' original mission. Meduson and the Imperial Army units were eventually able to locate the Eldar enemy's node complex that they had sought to destroy. In the meantime, Santor's force discovered signs that Ferrus Manus had somehow vanished. The initial assault by the Iron Hands strike force was temporarily halted by a powerful protective energy field that stymied their efforts as well as a powerful Eldar defence force that managed to halt the fierce and taciturn Iron Hands for quite some time. First Captain Santor eventually arrived and helped to coordinate a plan of attack. Within the cavernous depths, Ferrus Manus continued to explore until he was suddenly attacked by the serpentine creature that had been following him. The massive silver wyrm proved to be a vicious and deadly foe, and nearly slew the Primarch several times. During the ensuing battle, the Primarch was distracted by a sense of deja vu and a vague sense of prophetic vision concerning the words Angel Exterminatus, which appeared in his mind unbidden. Concocting a counter-attack against the massive creature, Ferrus was inspired by the memory of his brother Vulkan and managed to wound the serpent, forcing it to retreat. Elsewhere, the two Eldar responsible for sharing these visions with Ferrus Manus lament their allowance of an aspect of Chaos to encroach into their demesne when they kidnapped the Primarch. On the surface, Santor puts his assault plan into action. At first, the combined-arms assault goes well as the Iron Hands manage to penetrate the energy field, until the strange sorcery that afflicted their bionics earlier somehow returns, forcing them to make a tactical withdrawal. Brother Henricos once again makes an unusual request and offers to volunteer to lead a detachment of Imperial Army troops into the breached area of the shield and eliminate the Eldar threat. But to do so, Henricos detaches his only augmetic - his bionic hand - the symbolic symbol of the X Legion. At first the senior Iron Hands are initially hostile to this audacious plan, for it goes against their credo that the flesh is always weaker than the machine, but seeing no other option they reluctantly acquiesced to their subordinate's plan. Meanwhile, Ferrus Manus continued on his strange psychic journey, eventually reaching a bizarrely constructed, ancient throne with a rotting corpse sitting upon it. Coiled around it was the great serpentine wyrm that he had encountered earlier. The Iron Hands Primarch came to believe that this must be the spirit of Asirnoth, the dread wyrm of Medusa, that he had slain long ago. Wrestling with the massive creature, he was shocked by its sudden transformation as the wyrm shapeshifts into the all-too familiar form of Fulgrim, which informed the Primarch that he is not Asirnoth. Angrily, Ferrus slew the corrupted half-Primarch/serpentine beast, before tearing the corpse-king from its throne, opening a concealed doorway behind it. The Primarch then confronted his Eldar kidnappers and demanded his release, brushing aside their claims that they were merely trying to forewarn him against a likely future. Frightened for their lives, the Eldar grant the Primarch leave. On the surface, things are not going well, as Bion Henricos' non-augmented force of mortal Imperial Army troops takes massive casualties and he is sorely wounded in the process. But despite these setbacks, Henricos' force strikes a solid blow against their Eldar attackers. Before they are about to be wiped out, the Primarch appears as if from nowhere from beneath subsurface caverns and helps turn the tide of the battle. With the arrival of Santor and his heavy reinforcements, the Iron Hands quickly carry the day. As a sign of respect, the surviving Imperial Army troops are inducted as the first members of the Iron Hands mortal Auxilia forces; the Chainveil -- the adopted Sons of Medusa. They stand as a resolute reminder to the X Legion that not all flesh is weak. When asked about his recent whereabouts, Ferrus Manus refused to answer questions about his experience, claiming that nothing of import occurred. In response to vox hails from his brother Vulkan, Ferrus Manus then lead his Iron Hands into the jungle regions of the planet. In another place entirely, the two Eldar rue their failure, but take solace in knowing that even if the Primarch known as The Gorgon should fall, there is still another that would suit their purposes.
 * c. 002.M31 Pacification of Schravaan - This was a joint Imperial Compliance conducted by the Luna Wolves, Iron Warriors, Imperial Fists, and the Emperor's Children Legions against the xenos Badoon on the world of Schravaan. The Iron Warriors won a great victory when they stormed the final refuge of the Badoon. They breached the defences and held while the other Legions carried the city beyond. During the following victory feast, Horus proclaimed Perturabo the greatest master of siege warfare in the Great Crusade. Fulgrim, the Primarch of the Emperor's Children then inquired to his brother Dorn whether he thought even the defences of the Imperial Palace could resist the Iron Warriors, in which Dorn replied that he regarded the defences as being proof against any assault if well-planned. Perturabo flew into a rage and unleashed unfounded accusations against his brother. After this the two rarely spoke, and neither Legion would serve again in the same campaign for the remainder of the Great Crusade.
 * c. 002.M31 Compliance of Krypt - The Compliance of Krypt was a relatively short campaign conducted during the Great Crusade by both the Luna Wolves and the Death Guard Legions against the Orks upon the frozen plains of the world of Krypt. Fighting together for more than a week across the frozen surface of the planet, the Space Marine Legions turned the blue ice dark with xenos blood. The Luna Wolves' Captain Garviel Loken and his 10th Company are known to have fought alongside Death Guard Battle-Captain Nathaniel Garro and his 7th Great Company at this time.
 * c. 002.M31 Compliance of Fortrea Quintus - The world of Fortrea Quintus had been isolated from Imperial rule for several centuries, and when the leading edges of the Great Crusade reached the frontier of their star system, the planet's governing monarchy proved unwilling to submit itself to Imperial rule and had the Emperor's representatives executed. The Word Bearers were the nearest Legion to the world, though they were already heavily engaged in fighting Orks in the Chairak Nebula. Lorgar despatched 2,000 Astartes to Fortrea Quintus with orders that the planet be pacified within three months. The Word Bearers quickly established fortified positions on the planet and found the populace to be living in abject poverty, while their corrupt and ruthless rulers grew fat off their hard labours. A well-trained and disciplined army defended the planet's rulers, equipped with advanced weaponry and artificially-intelligent war machines. Under the command of Captain Jarulek, the Word Bearers steadily pushed their enemies back, their captain rousing the populace against their rulers with stirring speeches and fiery oratory. In ever-increasing numbers, the people of Fortrea Quintus joined Jarulek's march until his army numbered more than a million people. A month after the Word Bearers had landed, Captain Jarulek, together with his millions of new followers, launched his assault on the planetary ruler's last bastion, the Palace of Light. The casualties amongst the populace were horrendous,with thousands dying every minute as they charged the heavily defended walls, armoured bastions and labyrinthine trench systems of the main gates armed with little more than pistols and spears. As the carnage continued at the main palace gates, the Word Bearers attacked on another front, catching the defenders off-guard and striking for the heart of the palace. Nothing could stand before them and Jarulek himself captured the planet's ruler, throwing him to the blood-maddened survivors of the battle at the gates where he was torn to bloody shreds. Fully 90% of the people who had joined Jarulek's march died in the battle for the main gates, whilst barely a handful of Word Bearers had been killed. Following the victory, Jarulek began the Imperial indoctrination of the populace. When the Adepts of the Ministorum arrived to bring the word of the Emperor to Fortrea Quintus, they were horrified by the Word Bearers careless use of the populace, but found the people as well versed in the culture of the Imperium as any Loyal world could be. But when the Horus Heresy began, Fortrea Quintus would be revealed as a hotbed of Chaos worship secretly planted by the Word Bearers. After the end of the Heresy, the Ultramarines Legion would be forced to purge the planet of its festering Chaotic corruption by exterminating its population.
 * c. 003.M31 Compliance of Sixty-Three Nineteen - The Imperial Compliance action of the world codified as Sixty-Three Nineteen (63-19) took place in the 203rd year of the Great Crusade. Forced off course by a Warp Storm, the Luna Wolves' 63rd Expeditionary Fleet discovered a system of 9 planets orbiting a yellow sun quite by accident. After entering the system they were contacted by a technologically-advanced human society based on the third planet. This world was ruled by a self-appointed "Emperor of Mankind" who claimed to be the predestined ruler of all the scattered remnants of humanity across the galaxy. He invited a delegation from the Imperial fleet to treat and pay fealty to him. The Warmaster sent his most favoured commander, Captain Hastur Sejanus and his Glory Squad to meet with this supposed "Emperor." Though initial negotiations appeared to proceed smoothly, they irrevocably broke down when the Astartes Captain dared to suggest that there was another, true Emperor of Mankind. Perceived as an insult, Captain Sejanus and his men were taken by surprise during a diplomatic parley and cut down. The death of Horus' favourite son and Mournival member would open an emotional chink in the Primarch's psyche that would later be exploited by First Chaplain Erebus of the Word Bearers Legion upon the Feral World of Davin during Horus' corruption by Chaos in the Temple of the Serpent Lodge. Though intensely grieved by Sejanus' death, Horus miraculously did not order an immediate retaliatory strike. Instead, he mobilised an Astartes "speartip" unit to stand by and prepare for a planetary assault. Horus then attempted to negotiate a second time by despatching Maloghurst and another contingent of Luna Wolves, but this mission also ended in disaster when Maloghurst's Stormbird was shot down and presumed lost. A great fleet of over 600 warships rose up from the planet's atmosphere to meet the 63rd Expeditionary Fleet, throwing down a challenge. The Warmaster responded in kind. The great naval battle that ensued is not recorded in detail in the existing Imperial records of this time, but eventually the Imperial fleet ultimately prevailed. The massive ground assault spearheaded by the Luna Wolves was led by First Captain Ezekyle Abaddon, as well as a half-dozen Titans which provided ground support while Assault Craft provided close-air support. The Luna Wolves were eventually able to close and penetrate the capital city's defences. The Luna Wolves fought their way inside the Imperial Palace until they came face-to-face with the supposed "Emperor." The false Emperor offered to surrender to the Imperial forces, but only to their overall acting commander, not his subordinate captains. The request was transmitted to the fleet, but Captain Garviel Loken of the 10th Company quickly realised that this was merely a ruse to draw Horus down to the Throne Room to be assassinated. 1st Company Captain Kalus Ekaddon, commander of the Catulan Reaver Squad, swiftly killed the man he believed to be the false Emperor. Then the true false Emperor revealed himself, striking with deadly force against those Luna Wolves that were present, and nearly succeeded in neutralising both Loken, Ekaddon and the other members of the Catulan Squad. He was only stopped by the timely intervention of the Luna Wolves' Primarch, as Horus teleported directly into the Throne Room and slew the false Emperor with a single, well-aimed Bolt Pistol shot to the head. The main part of the campaign was concluded with the death of the false Emperor. With the death of their leader, the main resistance on 63-19 collapsed, although there were some elements of the world's military forces that continued to wage a guerrilla war around the planet as well as three other worlds within the system. These resistance elements were eventually expunged through the efforts of the 63rd Expedition's attached Byzant Janizars Imperial Army regiment over the next few months. The last pocket of serious resistance to Imperial Compliance occurred in the Whisperhead Mountains located in the southern hemisphere. This last pocket of resistance would eventually be excised by Captain Garviel Loken's 10th Company over a period of three months. These hold-outs made their final stand within a formidable fortress carved out of the rock of one of the range's highest peaks. When the 10th Company fought their way inside the mountain fortress they discovered what appeared to be several primitive religious fanes or shrines. The Luna Wolves presumed that they were somehow connected to this region's superstitious worship of a being referred to as Samus. This being turned out to be a minor daemonic Warp-entity who had dwelled on and interacted with the inhabitants of 63-19 for many millennia. During the ensuing battle Samus possessed the body of one of the 10th Company's sergeants and was able to eliminate over a dozen Astartes and a number of Remembrancers that had accompanied the Luna Wolves before being cut down by the combined Bolter fire of Captain Loken and Sergeant Nero Vipus. The two Luna Wolves fired over 90 Bolter rounds into the possessed sergeant's body and then incinerated the remains with a Flamer. This was the first recorded incident in Imperial history of its military forces encountering the malefic powers of Chaos. The entire course of events was classified on the orders of the Warmaster, in order to hide the fact that an Astartes had turned on his fellow Battle-Brothers and that it was possible for the supposedly invincible Astartes to be corrupted by the malignant powers of Warp-entities, who were themselves a well-kept secret of the Imperium. Overall governorship of the world after it was brought into Imperial Compliance was given to General Rakris of the Byzant Janizars, while the adaptation of the cities and infrastructure of the world to Imperial standards was given over to Peeter Egon Momus. 63-19 was the first world that the newly-arrived Remembrancers of the 63rd Expedition added to their own records of the Luna Wolves' exploits.
 * c. 003.M31 Cleansing of Laeran - Shortly after the beginning of their participation in the Great Crusade on their own terms, the Emperor's Children 28th Expeditionary Fleet encountered a hitherto-unknown serpentine alien race who called themselves the Laer. Analysis of captured scouts and envoys showed the Laer to be concentrated in a single star system on a single homeworld completely covered by a global ocean called Laeran (officially codified as Twenty-Eight-Three). Nonetheless, they had the potential to be a powerful foe. Like the Emperor's Children themselves, the Laer prized perfection in all aspects of civilisation. By the use of chemical manipulation from birth, individual Laer were adapted to their roles, whether they be workers, soldiers, diplomats, even artists. Observers from the Adeptus Administratum wondered if perhaps the Laer might be made a protectorate of the Imperium as conquering such an efficient race could prove to be a long and costly endeavour. Fulgrim refused any notion of co-operation. Only humanity was perfect, he insisted. For an alien race to hold its own ideals to be comparable to those of humanity was blasphemy in its most blatant form, and deserved nothing less than annihilation. He ordered his Lord Commanders to attack immediately, beginning a war that the Council of Terra predicted would last for decades. Fulgrim heard this prediction, and shook his head. In one month`s time, he promised, the Imperium would rule Laeran. The Emperor's Children, in concert with Lord Commander Fayle's Imperial Army regiments of the Archite Palatines, attacked the Laer in space, on the surface of their world, beneath their oceans and over the hulls of their orbital platforms. Laeran itself was a remarkable world in which the serpentine Laer had used anti-gravity technology to float massive coral platforms above their world's ocean where they chose to live after global warming had sunk all of Laer's continental masses. Everywhere the Astartes faced enemies adapted to their conditions by genetic enhancement -- warships connected directly to their crews' minds using cybernetic technology, the Laer's amphibious warriors could breathe underwater through gills, their scouts were capable of moving as fast as a Land Speeder, their gunners possessed eyesight that allowed them to target individual Space Marines miles distant. The casualties on both sides were horrendous -- it is estimated that, if not for the excellence of the III Legion's Apothecaries, more than half of its warriors would have died from their wounds. The Laer never surrendered -- their last warriors died fighting in the ruins of their capital city to protect their central temple dedicated to the worship of the Chaos God Slaanesh. One month after he had begun the attack, Fulgrim planted a standard displaying the Imperial Aquila over their corpses, leaving it the only thing standing unblemished on Laer. Over seven hundred of his men were dead, six times that number injured, but Fulgrim believed he had kept his promise. Against the most finely-honed alien warriors ever encountered, humanity had proven itself more powerful.Of course, the conquest of the Laer represented the beginning of Fulgrim and the entire III Legion's damnation and the beginning of their turn away from the service of the Emperor. Yet the Laeran System, for ten thousand standard years now, has been home to three Imperial cities and a dozen mining colonies, and all traces of its former xenos rulers and their corruption are gone.
 * c. 003.M31 Compliance of Murder (Urisarach) - The Death World of Urisarach (officially codified as One-Forty-Twenty but unofficially dubbed "Murder" by the Astartes who fought there) was the twentieth world encountered by the 140th Expeditionary Fleet, a contingent of the IX Legion of Astartes, the Blood Angels, commanded by Captain Khitas Frome. Unable to translate the warnings from the orbiting satellite beacons surrounding the world by the advanced human civilisation known as the Interex that warned approaching starships to stay away from Urisarach as a dangerous xenos species had been quarantined there, Captain Frome ordered his fleet's entire contingent of three companies of Space Marines to begin landing operations to investigate and bring the planet into Imperial Compliance. Due to the extreme atmospheric turbulence present on the world, all of the Blood Angels' assault craft attempting to land on the planet became scattered and were thrown far off-course, leaving the Imperial landing parties isolated from one another. The turbulent atmosphere also affected Vox (radio) communications and made it difficult for the Imperial forces to coordinate their movements. Ground teams soon started sending garbled transmissions to the fleet's vessels in orbit, reporting that the planet was inhabited by an extremely hostile intelligent arachnoid species, later dubbed the Megarachnids. The Megarachnids were an old enemy of the Interex civilisation, who had exiled the surviving members of the species to the world they called Urisarach as an act of mercy rather than committing xenocide as was standard policy for the Imperium. The Interex stripped the Megarachnids of their interstellar travel capabilities. The Megarachnids constructed weather control devices that created powerful atmospheric disturbances and interfered with radio communications in the shape of large "trees" across the planet. As reports of horrific combat from the surface continued, the xenos were described as too numerous and formidable to defeat without reinforcements. Not long afterwards, the Blood Angels made urgent distress calls requesting immediate reinforcements and extraction. The last transmission received by the fleet of the 140th Expedition came from Captain Khitas Frome himself, who noted through clenched teeth, "This. World. Is. Murder." This name stuck, becoming the Imperium's informal appellation for Urisarach. A company of Astartes from the III Legion, the Emperor's Children, arrived in response to the Blood Angels' distress calls. They made the same mistakes during the initial assault as the Blood Angels, and their landing were scattered by the planet's powerful atmospheric disturbances. The company took heavy casualties but just as the Emperor's Children were about to be overwhelmed, a relief force of newly-arrived Luna Wolves Astartes from the Warmaster Horus' own 63rd Expeditionary Fleet began to land through the breach in the atmosphere. The Megarachnids assaulting the Emperor's Children were scattered and a full-scale Space Marine assault on the hostile xenos of Murder began in earnest. Ten companies of Luna Wolves, the remnants of the Emperor's Children's company, tens of thousands of Imperial soldiers drawn from the Imperial Army's Byzant Janizars, and several Legio Mortis Titans proceeded to level entire swathes of the grass stalk forests and destroy every one of the atmosphere-altering "trees" they encountered, which steadily eroded Murder's atmospheric barrier. The Warmaster Horus, who commanding the Imperial assault from his flagship Vengeful Spirit in orbit, was very pleased with the progress being made. Some consideration had been paid to initiating a withdrawal from Murder now that a proper landing zone was available to allow an easy extraction of the troops, when an unexpected visitor suddenly arrived. The Primarch Sanguinius had come to Murder to inspect the dead of his original Blood Angels landing force that had been wiped out early in the campaign. With tears in his eyes Sanguinius asked his brother Horus if he would join him in a campaign of vengeance against the foul xenos. The Warmaster replied: "Yes, let us murder Murder." Adding 5 companies of Blood Angels to the Imperial invasion force, Sanguinius fought alongside the Warmaster against the aliens. Thousands of Megarachnids poured out of the forests and canyons of Murder in an endless wave. Despite never retreating from the Imperial assault, the Megarachnids only continued to lose ground. By the sixth month of the campaign it seemed the Megarachnids would soon face extinction, when a fleet deployed by the Interex arrived in-system to determine who had assaulted the Megarachnids' reservation world. Finding contact with the highly-advanced humans of the Interex to be a more pressing issue that needed to be dealt with, the Warmaster ended the campaign against the xenos of Murder. The Megarachnids had been saved from extinction for a second time by their old enemy. Imperial records do not indicate the final fate of this savage species once the Horus Heresy began.
 * c. 003.M31 Interex Compliance - The Interex was a highly advanced civilisation of humans that maintained a close alliance with various xenos races, including the ape-like Kinebrach. In many ways their technology was even more highly advanced than the technology employed by the Imperium at its height. Their world of Xenobia was first encountered by the 63rd Expeditionary Fleet during the Great Crusade. The Interex were devoted to fighting the menace of Chaos (referred by them as "Kaos") and were therefore highly suspicious of the Imperium's intentions, as they believed that the interlopers from Terra might be servants of the Ruinous Powers. While Horus and his Mournival were treating with the leaders of the Interex, First Chaplain Erebus of the Word Bearers, who had been accompanying the Warmaster as part of his entourage and who was already a secret follower of the Chaos Gods like most members of his XVII Legion, infiltrated the Hall of Devices on Xenobia, a museum that contained various artefacts and weapons drawn from the history of the Interex and their allied alien species. His objective was to steal the highly valuable and deadly Kinebrach blade known as the Anathame, a Chaotic artefact sacred to the Plague God Nurgle. After claiming the blade, Erebus rigged the building to explode to make good his escape. Feeling betrayed by the Imperials, who they took for agents of Chaos for stealing a known Chaotic artefact, the Interex's troops immediately attacked the bewildered forces of Horus, sparking a deadly confrontation. The Warmaster was evacuated off-planet by his Astartes as the Luna Wolves unleashed their full might upon the Interex. The Anathame would later play a pivotal role in the corruption of Horus by the Dark Gods upon Davin's Moon. The Interex were later destroyed by an Imperial campaign and all of their worlds were brought into Imperial Compliance.
 * c. 003.M31 The Council of Nikaea - A great Imperial conclave called by the Emperor of Mankind during the early 31st Millennium on the world of Nikaea in the midst of the Great Crusade that was intended to determine whether or not the use of psychic sorcery represented a boon or a grave danger to Mankind and the newborn Imperium of Man. Ultimately the existence of psykers in the Imperium was allowed but tightly restricted under centralised Imperial control, while the potent and unrestricted use of psychic abilities that was defined as sorcery was officially banned. The psychically powerful Primarch Magnus the Red and his Space Marine Legion the Thousand Sons would continue to study such powers in secret on their homeworld of Prospero, ultimately leading to their damnation by Chaos during the early days of the Horus Heresy.
 * c. 003.M31 Diasporex Persecution, Battle of the Corollis Star - During the latter part of the Great Crusade, the Iron Hands Legion's 52nd Expeditionary Fleet encountered a nomadic, fleet-based civilisation composed of both humans and xenos known as the Diasporex. The Iron Hands shared the Imperial Truth of the Emperor of Mankind and offered the human members of the Diasporex the opportunity to separate from their alien allies and to join the newly forged Imperium, but they declined the Astartes' offer. Their offer rejected, the Iron Hands passed judgement, and in the following months the Iron Hands fleet attempted to annihilate the Diasporex, but they proved to be highly skilled and experienced in the realm of naval warfare, and managed to easily evade crucial battles and even to severely damage the Iron Hands' Strike Cruiser Ferrum. The Emperor's Children of the 28th Expeditionary Fleet were called in as reinforcements, and so, a joint Imperial strike force composed of both the Iron Hands and forces from the Emperor's Children Legion prepared to launch an all-out assault against the willful Diasporex. Though the Diasporex knew that a powerful fleet of warships was hunting them and sought their destruction, they refused to leave the sector and move on to someplace safer. The Iron Hands' scout ships soon discovered the truth -- the Diasporex used hidden solar collector arrays hidden near the Corollis Star to collect fuel for their vessels. This was the reason why the Diasporex remained within the sector. Attacking these vital fuel stations, the two Imperial Expeditionary Fleets drew the Diasporex fleet out into open battle as the human-alien alliance sought to avoid utter annihilation at the Imperials' hands. During the massive naval battle that ensued Fulgrim's personal gunship, the Firebird, came under heavy attack and soon found itself in trouble. Rushing to his brother's side, Ferrus Manus' flagship, the Battle Barge Fist of Iron, came rushing to the rescue of his beleaguered brother. To restore his wounded pride, Fulgrim led a brief shipboarding action where the Emperor's Children wreaked bloody havoc on the troops of the Diasporex. But ultimate victory was robbed from him when the enemy ship's bridge was taken by one of his subordinate commanders. For months thereafter, Fulgrim would resent The Gorgon's actions, unable to truly understand the altruism of Ferrus' deed and the loss of life his selfless act had incurred on his Legion. Under the malignant influence of the daemon-possessed Laer blade that he wore at all times, Fulgrim could only see self-aggrandisement in his brother’s action, instead of the the heroic deed it had truly been. Ferrus's critical comments, the wounding darts that Fulgrim believed were meant to undermine him, were in actuality only jests designed to puncture Fulgrim's self-importance and restore his humility. What Fulgrim perceived as Ferrus' prideful boasts and rash actions had been deeds of courage that he spitefully dismissed as the influence of Chaos began to claim the Phoenician's soul.
 * c. 004.M31 Battle of Tarsus - At some unknown point during the Great Crusade, Primarch Fulgrim met with the renowned Eldar Farseer Eldrad Ulthran of Ulthwé Craftworld on the Maiden World of Tarsus, in which the Farseer attempted to warn Fulgrim of the Warmaster's corruption after being wounded by a malefic Chaos blade known as the Kinebrach Anathame at the hands of the traitor Eugen Temba upon Davin's Nurgle-corrupted moon. Temba had been the former Planetary Governor of the Feral World of Davin who had fallen under the influence of the Plague Lord Nurgle. The injury caused by the poisonous blade had allowed the Chaos Gods to gain a purchase on the Warmaster's soul. Fulgrim reacted with violent outrage at the Farseer's accusations due to his close kinship with his brother Horus, as his bond with the Warmaster was second only to that shared with Ferrus Manus, the Primarch of the X Legion. This outrage was further enhanced by the corrupting influence of Fulgrim's Laer daemonblade, which darkly influenced the Primarch to reject the Eldar's truth and provoked Fulgrim into launching an unprovoked and furious attack on Eldrad and his retinue alongside his Emperor's Children Captains and his personal Phoenix Guard. In the battle that ensued, the Emperor's Children slew both the revered Eldar Wraithlord Khiraen Goldhelm and a potent Avatar of Khaine, which forced the Farseer and the other Eldar troops to sorrowfully withdraw, as they realised that Chaos had already claimed yet another of the "Mon-Keigh's" Primarchs. Yet they had succeeded in killing all of Fulgrim's elite personal Phoenix Guard before their departure. Believing the Eldar had proven themselves a treacherous xenos race that sought to divide and conquer the Imperium by spreading such lies about its leaders, Fulgrim, again under the increasing influence of the daemonblade, ordered the destruction of several other beautiful Eldar Maiden Worlds using hideous virus bombs.
 * c. 004.M31 Battle of Deep Orbital DS191 - Weeks later, following the campaign on Tarsus, Fulgrim's fleet was ordered by the Council of Terra to rendezvous with the Warmaster's 63rd Expeditionary Fleet to inquire about reports of the their recent conduct and acquire information in regards to Horus' grave injuries acquired on Davin's feral moon. Most unusual, was that the III Legion's Lord Commander Vespasian was excluded from this delegation to Horus, which demonstrated an ever-growing rift between the Lord Commander and his Primarch. Following this delegation to the 63rd Expeditionary Fleet, Fulgrim announced to his senior commanders that he would lead a small force to join Ferrus Manus and his Iron Hands at Callinedes IV in the Callinedes System under the pretense of clearing it of an Ork infestation. The Primarch spearheaded the assault during the pacification of Deep Orbital DS191, leading the 1st, 2nd and 3rd Companies. During the assault, Captain Solomon Demeter, commander of the Emperor's Children's 2nd Company, found himself unsupported by the 1st and 3rd Companies as the battle-plan had laid out. Overextended and in real danger of being cut off and destroyed, the 2nd Company was only saved from certain destruction by the unplanned and timely arrival of the 10th and 13th Companies under the commands of Captains Saul Tarvitz and Lucius, two junior officers that Demeter had found himself associating more and more with as he was systematically frozen out by the III Legion's high command. A dark shroud hung over Lord Commander Vespasian after witnessing these dishonourable actions. He felt obliged to act after he observed Solomon Demeter's 2nd Company being intentionally abandoned by both Captain Kaesoron's and Vairosean's companies. It was a decision that would cost the honourable Astartes his life when he was murdered by Fulgrim himself.
 * c. 004.M31 Battle of Davin's Moon - Sixty Terran years after the world of Davin was brought into Imperial Compliance, Horus was influenced by the Word Bearers' First Chaplain Erebus to return to the feral planet. He informed the Primarch that the Imperial Governor of the world, Eugen Temba, had turned from the light of the Emperor, and foresworn his oaths of fealty to the Imperium. According to Erebus, Temba had found the inhabitants of Davin's moon unwilling to comply with Imperial rule, and so the Planetary Governor had led an occupying force to the moon in an attempt to bring the wild tribes of the moon into the light of the Imperial Truth. But during the parley with the tribesmen, Temba and his men were struck down by a sorcerous attack that twisted their perceptions away from their loyalty to the Imperium, and they succumbed to the temptations of power and immortality offered by Chaos and more specifically by the Plague God Nurgle, who claimed Davin's moon -- and Temba -- for his own. Horus personally led a combined assault force of Luna Wolves, an Imperial Army regiment of Byzant Janizars, and a detachment of Titans of the Legio Mortis onto the moon's surface. They soon discovered the wreck of Temba's flagship, the Glory of Terra, which was now a ruined derelict. The mass grave of rotting bodies of the Imperial Army garrison left on Davin were found in the nearby swamp, wearing the remnants of the uniforms of the 63rd Expeditionary Force. They seemed to confirm that Temba and all his men had perished, but this was not the case. The corpses of the Imperial Army troops were reanimated through the power of Nurgle as Plague Zombies that emerged from the swamps and attacked the Imperial forces en masse. The Luna Wolves and Byzant Janizars cut down the reanimated corpses. After this confrontation, the Warmaster led a speartip assault of Astartes into the derelict flagship. The bloated, mutant form of the Nurgle-corrupted Imperial Governor was discovered deep within the rotting vessel by Captain Verulam Moy of the 19th Company. Temba attempted to convert the Luna Wolves captain to Chaos, but Moy refused, and so the corrupted governor cut him down. Horus arrived shortly thereafter to confront the Temba, whose long-deceased body was now grossly enlarged, swollen with the corpulent putrescence of Nurgle. During their confrontation, the Warmaster discovered that Temba's corrupted form was immune to most forms of conventional injury. Horus also noted that Temba seemed to posses preternatural swiftness for a being so bloated and bulky, as well as formidable skill in swordsmanship. Horus fought like never before, his every move needed to parry and defend. Eugan Temba had never been a swordsman, so where his sudden, horrifying skill came from Horus had no idea. This was most likely due to Temba being armed with the stolen Kinebrach Anathame, the xenos Chaotic weapon that had been secretly stolen only scant weeks earlier from the Interex's Hall of Devices on Xenobia by the scheming Word Bearers First Chaplain Erebus. The Anathame was a tailored weapon, a blade of sentient metal dedicated to Nurgle that had been crafted by the Kinebrach metallurgists, using a technique now utterly forbidden by the Kinebrach's Interex allies. When such a blade was selected for use against a specific target, it became that target's nemesis, utterly inimical to the very molecular being of the chosen target. During the vicious battle, Temba stabbed the fell blade into the Warmaster's shoulder where his Power Armour had been torn away. Though in agony, Horus managed to finally subdue his foe and mortally wound him. As the corrupting power of Nurgle fled his ravaged and decaying body, Temba was wracked with guilt over what he had done. Before dying, he attempted to warn Horus against the power of the entities that lived in the Warp. Temba prophesised that only Horus could avert a grim future of never-ending war, where the Emperor was trapped in living death and Mankind was held in bondage to a nightmarish hell of bureaucracy and superstition. The spark of life finally fled Eugen Temba and he died, his soul consumed by the Warp. The wounded Horus was found by his Astartes and taken back to his flagship in orbit of Davin. Soon the Warmaster fell ill from the effects of the Anathame and was struck down by a mysterious malady sufficiently virulent to affect even his superhumanly resilient immune system. His mysterious illness was even beyond the skills of the Legion's Apothecaries to cure, and so, in desperation, Horus was brought to the surface of Davin to be "healed" in the Temple of the Serpent Lodge. First Chaplain Erebus had convinced the Sons of Horus to bring their Primarch to the Davinite priests, in direct violation of the Imperial Truth. The secret sect on Davin was really a Chaos Cult, and using sorcery (which had been outlawed by the Emperor at Nikaea) the cultists managed to warp the mind of the Warmaster against the Emperor by playing on the seed of jealousy and resentment that he felt for his father after the Emperor had left the Great Crusade behind to return to Terra. Magnus the Red, the Primarch of the Thousand Sons Legion, used his own potent command of sorcery to intervene and unmask Erebus, revealing his manipulations, but Horus' corruption by the power of Chaos Undivided could not be stopped as he gave in to his feelings of jealousy, egotism and bitterness. The Warmaster emerged from the Temple of the Serpent Lodge fully healed, but subtly changed in both mind and body, as he was now infused with the power of Chaos. Once Horus fully recovered, he finally took up the Emperor's offer to rename the Luna Wolves after himself as the Sons of Horus. He then schemed with the Astartes of his Legion's warrior lodge, aided and abetted by Erebus, to overthrow the Emperor and purge the XVI Legion of its remaining Loyalist elements. Horus intended to unleash the greatest betrayal in human history in pursuit of his own mad ambition.
 * c. 004.M31 Destruction of the Auretian Technocracy - Shortly after Horus' "miraculous" recovery on the Feral World of Davin, the newly renamed Sons of Horus encountered the human civilisation of the Auretian Technocracy on the world of Aureus during the Great Crusade. This human society had been founded during Mankind's early exploration of the stars during the Dark Age of Technology and had evolved along lines very similar to that of the Imperium, and more particularly to that of the Mechanicum of Mars. Horus and a contingent of Sons of Horus Astartes met with the Technocracy's leader, the Fabricator Consul, who represented the human government in its diplomatic talks with the Imperium. During their initial discussion aboard the landing bay of the Vengeful Spirit, Horus learned that the Auretian Technocracy made use of highly-coveted, lost Standard Template Construct (STC) technology. Upon learning this, the Warmaster turned his Bolt Pistol upon the Fabricator Consul and summarily executed him. He then ordered his men to annihilate the Fabricator Consul's personal guard who were known as the Brotherhood and who made use of Power Armour and weapons very similar to those of the Space Marines. Unknown to most of the Astartes within the Legion, the rot of corruption had begun to spread throughout the Legion shortly after Horus made his dark bargain with the Ruinous Powers. The official explanation for the Sons of Horus Legion's grievous actions against the Technocracy stated that the staff brought by the Fabricator Consul aboard the XVI Legion's flagship possessed a weapon which he planned to use to assassinate the Warmaster. This prompted the resulting conflict with the Auretian Technocracy which lasted for over six bloody months. The World Eaters fought alongside the Sons of Horus on the Technocracy's homeworld of Aureus, and their Primarch Angron personally lead the final Imperial assault on the Iron Citadel held by the Brotherhood of the Auretian Technocracy. When the blood-maddened warriors of the World Eaters' Assault Companies stormed a breach in the walls, the Brotherhood detonated explosive charges that buried the warriors under thousands of tonnes of rubble. Angron tore his way free and butchered the remaining warriors of the Brotherhood with his monstrous chain-glaive. Ephraim Guardia, the Senior Preceptor of the Brotherhood Chapter Command and Castellan of the Iron Citadel, died in the first seconds of Angron's attack. The campaign had been a brutal one, as the Brotherhood made use of highly advanced power armoured suits similar to those employed by Legiones Astartes, but they were eventually defeated and their technology was requisitioned by the XVI Legion. Horus would use the seized Auretian STC databases to entice a faction of the Adeptus Mechanicus to turn against the Emperor and join his rebellion. These Traitors would eventually form the core of what became the Dark Mechanicus and their treachery would unleash the terrible civil war within the Mechanicus that became known as the Schism of Mars.
 * c. 004-007.M31 Pacification of Arkenath - Ultramarines Legion's Captain Hektor, commanding 500 of his battle-brothers, helped prosecute the Emperor's Great Crusade to bring enlightenment to the galaxy and repatriate the lost colonies of man by fighting the Vektates of Arkenath. The Vektate were a deviant culture, an alien overmind that had enslaved the human populous of Arkenath. Hektor and his warrior brothers had shattered the yoke that bound their unfortunate human kin and in so doing had destroyed the Vektates. The human populace owed fealty to the Imperium, and demonstrated it gladly when they were free of tyranny. It had been a grim war. Captain Hektor's ship the Fist of Macragge had been involved in a brutal ship-to-ship action against the enemy, but had prevailed. Repairs had been conducted on Arkenath, as well as the requisitioning of a small tithe of men, eager to venture beyond the stars, to help replenish elements of the ship's crew. Once the war was over, Hektor and his battle-brothers had been summoned to the Calth System and the region of space known as Ultramar in preparation of the massive joint campaign of extermination with the Word Bearers XVII Legion against the Ghaslakh xenohold, a common mission for the Astartes during the final days of the Great Crusade. It would be at Calth that Lorgar would launch a surprise attack on the Ultramarines, later known as the Calth Atrocity whilst they were gathered for the campaign against the Orks of Ghaslakh. The XIII Legion would be caught completely unaware while the Word Bearers attempted to use the advantage of surprise to completely annihilate their hated rivals. The Fist of Macragge would never arrive, as they would be completely obliterated by the Word Bearers secretly-constructed warship, the Furious Abyss, while enroute to Calth.
 * c. 004.M31 Pacification of the Cheraut System - This was an Imperial Compliance action during the Great Crusade jointly conducted by Astartes from the Emperor's Children, Night Lords and Imperial Fists Legions. After the Night Lords Primarch suffered one of his violent fits, Fulgrim rushed to Curze's aid. The Night Haunter then confided in his brother the dire visions that he had seen; his death at the hands of their father, that many of the Primarchs would die fighting amongst themselves, and that the light the Emperor brought to his homeworld of Nostramo would destroy it forever. Troubled by these dire portents, Fulgrim confided in his brother Rogal Dorn. Dorn took exception to this slight on the Emperor's name and confronted Curze. Shortly thereafter, Dorn was found unconscious and bleeding with great gouges of flesh ripped away from his torso. Crouching above his fallen brother was the pallid form of the Night Haunter, weeping. Wracked with self-loathing and guilt, Curze was taken into custody and exiled to his chambers, while his brother Primarchs discussed what actions to take against their deeply disturbed brother. Hours later, when the council of Primarchs finally disbanded, they found Night Haunter missing and the Imperial Fists' honour guard watching over him butchered. By the time the Primarchs gave chase, Night Haunter had already disappeared with his Legion into the Warp.
 * c. 004.M31 Cleansing of Ariggata - This was an Imperial Compliance that was carried out jointly by the Ultramarines, Luna Wolves and the World Eaters Legions against the world of Ariggata. A technologically advanced world, the world of Ariggata had been isolated from the rest of humanity for many centuries, and when Imperial envoys arrived bearing word of the Emperor and the Imperial Truth, they were executed in a bloody gesture of independence. The military might of Ariggata was formidable, and thus the honour of its pacification fell to Warmaster Horus and two other Space Marine Legions under his command. Most of the planet was quickly conquered, except for the massive fortress within which most of the leaders of the planet cowered. Eager to be on his way, Horus commanded Angron, Primarch of the World Eaters, to take back the citadel and kill only the leaders. Eagerly, Angron led the assault. However, the fortress was heavily defended and the casualties were horrendous, a dozen World Eaters falling for a meter of land. Eventually, a ramp of corpses led up to a single breach in the wall, and the Astartes of the World Eaters Legion plunged in. Filled with rage over their fallen brothers, they were merciless. By the time the Ultramarines arrived, the battle was all but over. The inside of the fortress was filled with the dismembered and mangled corpses of the defenders, for not one soul had been spared the vengeful fury of the World Eaters. It was an absolute slaughter, the fortress having been transformed into an abattoir of human blood. The Ultramarines were disgusted by this savage behaviour and by the time the appalled Sons of Guilliman left the citadel, the Luna Wolves and the World Eaters had already departed, leaving the Ultramarines to garrison Ariggata until the Imperial Army arrived. Before Guilliman was able to confront his brother Primarchs regarding the massacre on Ariggata, the Horus Heresy erupted, both Horus and Angron spitting on their oaths of loyalty to the Emperor, and Guilliman's worst fears were confirmed.
 * c. 004.M31 Vulpa Straits Hrud Migration - Commanding the 51st Expeditionary Fleet, the Warsmith Barabas Dantioch led a large Iron Warriors contingent against a massive xenos incursion known as the Vulpa Straits Hrud Migration. Upon the Fortress World of Gholgis the Hrud infiltrated and destroyed the Iron Warriors garrison. The intense entropic fields generated by the migratory Hrud swarms caused stone to age and brought flesh to ruin, turning the Astartes warriors into so much dust and bones, rusting their armour and jamming their Bolters as the Iron Warriors' fortress crumbled all about them. Only then did the rachidian beasts creep out of every nook and crevice to attack, stabbing and slicing with their venomous claws. This left Warsmith Dantioch prematurely aged and crippled. Very few survivors made it out alive as Stormbirds extracted the survivors from the remains of Gholgis. Many of the Astartes died from premature ageing or were left in aged, superhuman bodies. In the Hrud Migration's aftermath, the worlds of Krak Fiorina, Stratopolae and Gholghis were lost. The Warsmith questioned Primarch Perturabo's prosecution of the Hrud extermination campaign, which left half a Grand Company dead. Dantioch soon found himself relieved from command of the 51st Expeditionary Fleet and permanently garrisoned to the world of Lesser Damantyne for his presumption.
 * c. 004.M31 Jorgall Execution – The Jorgall campaign was carried out during the Great Crusade against a xenos race of humanoid aliens known as the Jorgall by the Death Guard Legion. They possessed a basic humanoid anatomy and also bled dark crimson coloured blood, similar in colour to that of a human's. But their brain and central nervous system was located inside their chest cavity. Nearly all Jorgalli featured extensive cybernetic physical enhancements to improve their physical forms and enhance their fighting abilities, such as hands replaced by lethal claws, feet replaced by wheels for rapid mobility and teleoptic cameras for eyes as well as sub-dermal protective armour. Some Jorgalli even had basic Needler-type weapons implanted within the cavities of their bodies. They occupied the Tasak Beta and Fallon Systems in Imperial space. Elements of the 1st, 2nd and 7th Great Companies with Mortarion as the commander launched an assault into the main Jorgall cylinder world. This battleground was suited to the Death Guards' unique talents. The Jorgall breathed a mixture of oxygen and nitrogen with heavy concentrations of chlorine, a weak poison that a Death Guard Astartes' lungs could resist with little effort. First Captain Calas Typhon provided support for the Primarch while Commander Ignatius Grulgor penetrated the drive cluster and took out the control of the cylinder world's motive power centre. Battle-Captain Nathaniel Garro, alongside an elite cadre from the Sisters of Silence, neutralised the construct’s hatcheries. Following their hard-fought victory, there were dissenting voices from the Adeptus Mechanicus contingent aboard the warship Spectre of Death petitioning Mortarion for a few days in which to loot the alien craft of technology. The Primarch, as was his prerogative, refused the request. The letter of Malcador the Sigillite's orders -- and therefore, by extension, those of the Emperor Himself -- was that the Jorgall incursion into the sector was to be exterminated and nothing more. The master of the Death Guard clearly saw no point of confusion in those orders. Nothing was to be left of the aliens.
 * c. 004.M31 The Fall of Prospero  - After psychically spying on the Warmaster Horus' corruption by the Ruinous Powers of Chaos while he lay wounded and unconscious in the Temple of the Serpent Lodge on the world of Davin, the Primarch of the Thousand Sons Legion, Magnus the Red, realises that Horus will rebel against the Emperor of Mankind. Magnus violates the anti-psyker Edicts of the Council of Nikaea and resorts to the use of psychic sorcery to send a warning to the Emperor of Horus' treachery. The psychic sending disrupts the delicate psychic defences the Emperor had erected within the bowels of the Imperial Palace to protect his secret project to create a human extension of the Eldar Webway for the Imperium. The intrusion allows the daemonic denizens of the Immaterium to flood into the Imperial portion of the Webway and kill thousands of the Adepts and Tech-priests who had been labouring there on the Emperor's behalf . The Daemons also now present a dire threat to Terra itself, and the Emperor is forced to spend all of his time on the psychic amplifier known as the Golden Throne to keep the daemons from breaching the Webway and directly assaulting the homeworld of Mankind. Furious that Magnus had violated his express promise to give up the practice of sorcery, and sure that it is Magnus, and not Horus, who has been corrupted by the Warp, the Emperor orders an Imperial expeditionary force led by the Space Wolves Legion and its Primarch Leman Russ to go to the Thousand Sons' homeworld of Prospero and bring Magnus back to Terra to answer for his crimes. Horus tricks Russ into launching an all-out assault upon Prospero rather than just peacefully escorting Magnus back to Terra. Prospero's magificent capital city of Tizca is destroyed in the resulting battle and Magnus and the Thousand Sons are nearly destroyed by the Imperial assault until Magnus calls out to the Chaos God of Sorcery, Tzeentch, for aid. Tzeentch whisks the badly wounded Magnus and the entire Thousand Sons Legion away from Prospero to a Daemon World in the Eye of Terror later known as the Planet of the Sorcerers. Embittered by the Emperor's treatment of him, Magnus and the surviving Astartes of his Legion throw in their lot with Horus and the Traitors.
 * c. 004.M31 Pacification of Gugann and the Olympia Genocide - The Iron Warriors conducted a campaign against the xenos known as the Hrud upon the world of Gugann. It was during this campaign that Warmaster Horus broke the news to Perturabo that Olympia was in rebellion. The appointed Imperial Planetary Governor Dammekos had died and the population, incited by demagogues, had taken up arms. The thought of being the only Legion unable to hold its own homeworld appalled and infuriated Perturabo. By this time, Horus was fully corrupted by Chaos, and he sought to make the most of this opportunity. He presented Perturabo with the hammer Forgebreaker as a mark of respect, signalling the pact between the two Primarchs. There is still much debate whether this weapon was some kind of conduit through which the Ruinous Powers could manipulate the Iron Warriors Primarch. The IV Legion would go on to brutally suppress the population on their homeworld, committing genocide against 5 million civilians. This would seal their fate as the Iron Warriors become fully corrupted by Chaos during this campaign and they were easily swayed to join Horus' cause.
 * c. 005.M31 Signus Campaign - In the midst of the darkness of the Horus Heresy, the Blood Angels never wavered, but held true at the Emperor's side, and nowhere was this more true than during the events of the Signus Campaign. It is said that Horus hated and feared Sanguinius more than any of his brothers and wove many strategies to ensnare or slay him, though all failed. In an effort to weaken and divide the Loyalist forces, the Warmaster charged the Blood Angels Legion with the arduous task of cleansing the Signus Cluster -- a triple star system of the Segmentum Ultima near to the galactic centre. Sanguinius' Legion was ordered to cleanse the 7 worlds and 15 moons of Signus of xenos invaders and release the humans thereon from their xenos-overlords. Unaware of the Warmaster's perfidy, Sanguinius willingly obeyed his brother Primarch and immediately set out for this volatile region of space. Unbeknownst to the Blood Angels, they were blindly walking into a deadly trap, for the Signus Cluster had fallen prey to agents of the Ruinous Powers and become a veritable Realm of Chaos -- a system of hellish Daemon Worlds under the rule of a Greater Daemon of Slaanesh known as Kyriss the Perverse. When the Blood Angels arrived in-system, their fleet was ambushed by the malevolent forces of the Warp, crippling or killing many of their Navigators and Astropaths in the initial onslaught. The Blood Angels now faced the fury of Chaos for the first time. Kyriss sent an image of himself to Sanguinius, declaring his lordship over the system in the name of Slaanesh and taunting the Primarch into taking it back from him. Though they had never faced such a foe, the Blood Angels prepared their counterattack, sure that they would prevail. Rising to the challenge of the vile Greater Daemon, the Blood Angels Legion attacked the daemon host of Kyriss, launching a series of attacks across the seat of the daemon's power, the world of Signus Prime. Sanguinius faced the vast hordes of human cultists and packs of monstrous daemons as an Angel of Vengeance. Soon the planet was awash with the blood of both loyal Space Marines and thousands of slain cultists of Kyriss. The Primarch spearheaded the Blood Angels' assault on the Greater Daemon's seat of power, known as the Cathedral of the Mark, to confront and destroy Kyriss and reclaim the planet in the name of the Emperor. But soon Sanguinius came face-to-face with a new nightmare known as Ka'bandha, a Greater Daemon of Khorne. Within the pantheon of the Blood God, Ka'Bahnda is regarded as one his most prolific killers. He is a murderous engine of destruction, slaughtering in exalted joy for his lord Khorne. The daemon taunted the Primarch, and revealed Horus' treachery. Enraged by the daemon's mockery and fearing his claims to be true, the angelic Primarch fought the brutal Bloodthirster in single combat. Seizing the initiative during the battle, he surprised the Bloodthirster with his frenzied assault, stabbing his sword into the daemon's chest, ripping open a gaping wound. The massive creature roared in fury and pain, lashing out with his whip at the Primarch's legs. Sanguinius was momentarily unbalanced as his legs were crushed in the whip's coils. The daemon then smashed Sanguinius to the ground with the flat of his axe. The winged hero was stunned, helpless before the daemon's wrath. As his vision cleared he looked up at the mighty monster towering over him. The Greater Daemon taunted him one final time, let out a mighty bellow and then struck out across the battlefield, slaughtering 500 Space Marines with huge swathes of his mighty axe. They psychic backlash of the deaths of so many of his sons blasted Sanguinius into unconsciousness. It would not be until the closing days of the Horus Heresy that Sanguinius would once again be confronted by the savage Daemon Lord during the Battle of Terra. With the fall of their Primarch and the slaughtering of their brethren, the Blood Angels Legion was consumed by a black rage that drove them into a berserker's fury as they charged into the daemonic horde and in their madness they smashed the horde of daemons asunder. Yet the brutal violence of the daemon Ka'Bahnda had unleashed something dark within the psyche of the Space Marines, a thirst for blood later known as the Red Thirst that would not be slaked until every taint of Chaos had been erased from the planet. Even the mighty Kyriss was banished back to the Immaterium. Only when the planet was cleansed did the rage of the Blood Angels finally subside. Though Signus had been freed from its thrall to the Forces of Chaos, the cost of victory was far higher than any could have wished. The berserker rage the Blood Angels had experienced known as the Black Rage had left a brooding shadow on their souls that would manifest in the centuries to come as the great curse that would afflict the Blood Angels and their Successors.
 * c.005.M31 The Horus Heresy Begins - Whilst the Emperor gathers his Primarchs and leads them to glory over the course of the Great Crusade, the Chaos Gods spread whispers of corruption throughout the Space Marine Legions. Horus Lupercal, of the Luna Wolves Legion, is the greatest of the Primarchs to fall. A masterful strategist, Horus spreads the creed of Chaos to those of his brother Primarchs he deems susceptible. A full half of the Legiones Astartes follow Horus into the arms of Chaos, and the galaxy is plunged into a civil war from which it will never truly recover.
 * c. 005.M31 Battle of Calth - The Battle of Calth, also referred to as the Calth Atrocity, was the name given by later Imperial scholars to the treacherous campaign conducted during the early stages of the Horus Heresy in the 31st Millennium by the traitorous XVII Space Marine Legion, the Word Bearers, on behalf of the Warmaster Horus against their hated rivals, the XIII Space Marine Legion, better known as the Ultramarines. The campaign was launched by the Word Bearers' Primarch Lorgar Aurelian with the goal of exterminating the XIII Space Marine Legion outright. The purpose of the Word Bearers' invasion of the Ultramarines' Realm of Ultramar in the Eastern Fringe of the galaxy was to tie down the XIII Legion and prevent them from reinforcing their fellow Loyalists as the Traitor Legions marched relentlessly on Terra itself. The crux of the campaign came on the Agri-world of Calth in the Ultramar Sector, where the Ultamarines successfully broke the Word Bearers' surprise assault after a viciously-fought siege action, though at the cost of terrible casualties and the complete destruction of Calth's atmosphere and once-verdant biosphere. As a result of the devastation wrought by the Word Bearers during the Calth Atrocity, future generations of Calth's people were required to live deep underground in massive subterranean Hive cities to escape their world's radiation-scorched, airless surface. While both the Ultramarines and their Primarch Roboute Guilliman survived the Word Bearers' assault, the campaign successfully prevented the Ultramarines from participating in the Battle of Terra as Horus had planned.
 * c. 005-007.M31 Thramas Crusade - During the Horus Heresy the Warmaster Horus sent Night Haunter and his VIII Legion on a campaign of genocide against the Imperial strongholds of Heroldar and Thramas in the Aegis Sub-sector of the Eastern Fringes, thus protecting Horus' flank and delaying the Dark Angels Legion from reinforcing the Loyalists. This bitterly contested campaign dragged on for nearly three standard years. In an attempt to sway his brother Lion El'Jonson to Horus' cause, the Night Haunter left a deep-void beacon in the patrol path of one of the Dark Angels' outrider vessels. The beacon was set to transmit coordinates in advance, so that the two Primarchs could meet and parley on the planet of Tsagualsa. Night Haunter wanted to break his former brother either mentally, physically or both to obtain his objectives. The Primarchs were accompanied by two warriors from their personal Honour Guards to the parley. The meeting began amicably enough between the two as they conversed with relative civility. This amity lasted only until the Night Haunter slandered El'Jonson, and in return the Lion struck his former brother. This melee further degenerated into an all-out brawl between the two sides. As the Night Haunter strangled the life out of El'Jonson, one of the Dark Angels Honour Guardsmen ran his sword through the Night Haunter's back, saving his Primarch's life. Eventually both Legions sent reinforcements in response to this incident. Each side dragged away their respective Primarchs from the scene of the combat. Both Primarchs survived this brutal confrontation and went on to continue the contest between their Legions for control of the Aegis Sub-sector. When next they fought, the Dark Angels executed a meticulously planned ambush on the Night Lords' fleet while it was in transit across the sub-sector that saw the back of the Night Lords Legion broken and their Primarch mortally wounded after having faced his brother El'Jonson once again in mortal combat. Thanks to the skilled coordination and superb execution by the Lion, the Night Lords fleet was devastated, losing dozens of capital ships and approximately one-quarter of their Legion fleet to the Dark Angels' assault. Unfortunately, the remainder of the Night Lords fleet fled the Dark Angels' wrath, while the recently recovered Night Haunter, First Captain Sevatarion and the elite Night Lords Atramentar Terminators led a desperate boarding assault action upon the Dark Angels' flagship. This resulted in the death of all but a dozen of the Atramentar and the capture of Sevatarion and the remaining survivors. Konrad Curze fled El'Jonson's wrath, evading the Dark Angels for months, stalking the shadows within the bowels of the mighty capital ship. Somehow, the remaining Night Lords managed to affect their escape and fled into the void.
 * c. 005.M31 Battle of Istvaan Extremis - The elite 1st Companyof the Emperor's Children fought in concert with the Death Guard Legion's 7th Company under the command of Battle-Captain Nathaniel Garro against traitorous forces on Istvaan Extremis, the outermost planet within the Istvaan System. Whilst fighting against a powerful Slaaneshi psyker known as a Warsinger, Garro sustained serious injuries; crushing damage to his torso, arm and the loss of his right leg from the mid-thigh down. He was only saved from certain death by the timely ministrations of the Emperor's Children Chief Apothecary Fabius. Taking stock of the desperate situation, Lord Commander Eidolon made use of a hitherto unknown ability -- a modified tracheal implant bonded with his vocal chords, that allowed him to produce a nerve paralysing shriek similar to that employed by certain warrior breeds of the alien Laer. This powerful ability killed the Warsinger and helped the Astartes carry the day.
 * c. 005.M31 Istvaan III Atrocity - The terrible campaign that marked the start of the Horus Heresy and was known to later generations as the Istvaan III Atrocity began when the Imperial Planetary Governor of Istvaan III, Vardus Praal, had been corrupted by the Chaos God Slaanesh whose cultists had long been active on the world even before it had been conquered by the Imperium. Praal had declared his independence from the Imperium, and had begun to practice forbidden Slaaneshi sorcery, so the Council of Terra charged Horus with the retaking of that world, primarily its capital, the Choral City. This order merely furthered Horus's plan to overthrow the Emperor. Although the four Legions under his direct command -- the Sons of Horus, the World Eaters, the Death Guard and the Emperor's Children -- had already turned Traitor and pledged themselves to Chaos, there were still some Loyalist elements within each of these Legions that approximated one-third of each force; many of these warriors were Terran-born Space Marines who had been directly recruited into the Astartes Legions by the Emperor himself before being reunited with their Primarchs during the Great Crusade. Horus, under the guise of putting down the rebellion against Imperial Compliance on the world of Istvaan III, amassed his troops in the Istvaan System. Horus had a plan by which he would destroy all of the remaining Loyalist elements of the Legions under his command. After a lengthy bombardment of Istvaan III, Horus despatched all of the known Loyalist Astartes down to the planet, under the pretence of bringing it back into the Imperium. Initial attacks on the Choral City had washed away any feelings of unease, the release of the Loyalists' anger and hurt in bloodshed reassuring them that things were as they should be, and that their earlier misgivings were no cause for concern. But then Captain Saul Tarvitz of the 10th Company of the Emperor's Children had arrived with an incredible tale of betrayal and imminent attack. Many had scoffed at Tarvitz's warning, but some had immediately known the truth of it, and had fought to make their brothers realise their danger. As the monstrous scale of the betrayal sank in, the Loyalist Sons of Horus, World Eaters and Emperor's Children had raced to find shelter before the deadly viral payload struck the world intended to be their tomb. The Loyalists on the surface watched in horror as the first streaks of light lit up the sky and the detonations covered the skies in thick starbursts of deadly viral agents. The screaming of the city as it died haunted them, as they couldn't even begin to imagine the horror that must have filled the minds of those who watched as the Life Eater devoured the flesh of their loved ones, before reducing them to disintegrated hunks of rotted, dead matter. Many within the Loyalist ranks knew how deadly the Life Eater was, and they knew that within hours the entire planet would be a charnel house. Then the firestorm had come and razed the surface bare of any signs of its former inhabitants, burning them to ashen flakes on the wind as it destroyed all in its path and howled across the surface of Isstvan III in a seething tide of flame. The Primarch of the World Eaters, Angron, realising that the virus-bombs had not been fully effective at eliminating all the Loyalists, flew into a rage and hurled himself at the planet at the head of 50 companies of World Eaters Traitor Marines. Discarding tactics and strategy, the World Eaters Traitors worked themselves into a frenzy of mindless butchery fed by their growing allegiance to the Blood God Khorne. Horus was furious with Angron for delaying his plans, but Horus sought to turn the delay into a victory and was obliged to reinforce Angron with troops from the Sons of Horus, the Death Guard, and the Emperor's Children. Fortunately, a contingent of Loyalists led by Battle-Captain Garro escaped Istvaan III aboard the damaged Imperial frigate Eisenstein and fled to Terra to warn the Emperor that Horus had turned Traitor. On Istvaan III, the remaining Loyalists, under the command of Captains Tarvitz, Garviel Loken and Tarik Torgaddon, another Loyalist member of the Sons of Horus, fought bravely against their own traitorous brethren. Yet, despite some early successes that delayed Horus' plans for three full months while the battle on Istvaan III played out, their cause was ultimately doomed by their lack of air support and Titan firepower. During the battle the Sons of Horus Captains Ezekyle Abaddon and Horus Aximand were sent to confront their former Mournival brothers, Loken and Torgaddon. Horus Aximand beheaded Torgaddon, but Abaddon failed to kill Loken when the building they were in collapsed. Loken survived and witnessed the final orbital bombardment of Istvaan III that ended the Loyalists' desperate defence. To prove his worth and loyalty to Lord Commander Eidolon of the Emperor's Children -- and thus to his Primarch, Fulgrim -- Captain Lucius of the 13th Company of the Emperor's Children, the future Champion of Slaanesh known as Lucius the Eternal, turned against the Loyalists that he had fought beside because of his prior friendship with Saul Tarvitz. Lucius slew many of them personally, an act for which he was then accepted back into the Emperor's Children Legion on the side of the Traitors. In the end, the Loyalists retreated to their last bastion of defence, only a few hundred of their number remaining. Finally, tired of the conflict, Horus ordered his men to withdraw, and then had the remains of the Choral City bombarded into dust for a final time from orbit.
 * c. 005.M31 Battle of Phall - During the Horus Heresy, at the command of Horus, a large Iron Warriors contingent was sent to halt the encroaching Imperial Fists fleet that had originally been sent to Istvaan III to reinforce the beleaguered Loyalists. The Traitors could not allow such a strong complement of Astartes to infiltrate their controlled area of space, for they could seriously disrupt preparations for the Traitors' attack on Terra. Commanding over twenty large warships, Perturabo led his fleet in a sudden and devastating attack upon the Imperial Fists fleet in what became known as the Battle of Phall. Over a dozen vessels were ripped apart by the brutal hail of fire from the Traitor vessels. The Imperial Fists fought back, devastating the lead ships of the Iron Warriors' fleet, tearing them apart in a vicious firestorm. The Loyalists gained the initiative in the battle and managed to repel the Traitors' surprise attack, despite severe losses at the start of the engagement. Launching a counterattack, the Imperial Fists drove off the embattled Traitor fleet and managed to break orbit and manoeuvre to their jump points, to enter the Warp and make for Terra.
 * c. 006.M31 Drop Site Massacre of Istvaan V - The world of Istvaan V was the location of the infamous Drop Site Massacre where the Traitor Legions of the Warmaster Horus redeployed following the virus-bombing of the Traitor Legions' own Loyalist members at Istvaan III at the start of the Horus Heresy. Upon learning of the terrible atrocity Horus had committed, the Emperor deployed seven Loyalist Legions of Space Marines to bring Horus to account for his actions. The Iron Hands, Salamanders and Raven Guard made up the first wave of the attack, but were pushed back by the superior tactics of Horus's maddened Chaos Space Marines. The Loyalist reserves were called in, but the four Space Marine Legions comprising them -- the Iron Warriors, the Alpha Legion, the Word Bearers and the Night Lords -- had also secretly betrayed the Emperor and were prepared to follow Horus and swear themselves to Chaos. The three Loyalist Legions were almost annihilated in the resulting crossfire but several thousand survivors from each Legion managed to escape off-world, though they were too decimated to play much of a further role in the defence of the Imperium from Horus' betrayal. During the ensuing slaughter, Fulgrim came face-to-face with his former brother and closest friend, Ferrus Manus. The two Primarchs engaged in a titanic struggle, but in the end The Gorgon was mortally wounded, and with the urging of the Laer daemonblade that he always carried, Fulgrim beheaded the Iron Hands' Primarch. The civil war unleashed at Istvaan V pitched the whole Imperium into anarchy and chaos.
 * c. 006.M31 Raven Guard Infiltration - Shortly after the Drop Site Massacre on Istvaan V early in the Horus Heresy, and unbeknownst to Loyalists and Traitors alike, the Alpha Legion managed to infiltrate the remnants of the Raven Guard Legion, surgically altering Alpha operatives to resemble dead Raven Guard Space Marines and then inserting them into the ranks of the XIX Legion during the chaos of the Drop Site Massacre. Acting on information received from the alien organisation known as the Cabal, Alpharius Omegon believed that the XIX Legion was going to eventually receive an extremely valuable, top-secret asset from the Emperor that would prove to be of immense value to the Traitors' cause if it could be secured. In an operation personally overseen by Omegon, the Alpha Legion managed to appropriate the asset, which turned out to be a sample of pure Primarch gene-stock and related information on its genetic manipulation that the Primarch Corax had recovered from the Emperor's gene-laboratories beneath the Himalazian Mountains in the bowels of the Imperial Palace. Playing their typical game of deception and intrigue against all sides, Alpharius Omegon mislead Horus by surrendering tainted information about the pure Primarch gene-stock to the Traitors' chief geneticist, the Emperor's Children's Chief Apothecary Fabius Bile. However, Horus knew that the Alpha Legion might have infiltrated any Legion, and had ordered the Alpha Legion to be put under surveillance by other Traitor forces to prevent any double-dealing. Alpharius Omegon also mislead the Cabal, by not destroying the pure Primarch gene-stock as they had promised to damage the Loyalists' war effort, keeping it for their own benefit. However, the pure gene-stock had been infected by a daemonic virus that had been intended to make it worthless to the Raven Guard. The Alpha Legion had been assured by the Tech-adepts of the Dark Mechanicus that this daemonic taint could be removed once the Primarch gene-stock was in the hands of the Traitors, but whether this assertion proved to be correct remains unknown. A second, major objective of the Raven Guard infiltration by the Alpha Legion was the destruction of the Raven Guard's remaining stocks of gene-seed, thereby eliminating any chance that the XIX Legion could be rebuilt after the massacre on Istvaan V. However the Alpha Legion failed in this objective due to the heroism of the Astartes of the Raven Guard, and the XIX Legion was eventually able to reconstitute itself and play a crucial role in the future history of the Imperium.
 * Shadow Crusade (ca. 006.M31) - Enraged beyond the capacity for speech by the Word Bearers' betrayal of the Imperium and assault upon Ultramar, Roboute Guilliman gathered what vessels he could spare after Kor Phaeron’s ambush of the Legion fleet at Calth, drew additional numbers from the first Ultramarines relief fleet bound for Calth after the massacre above that world, and tracked Lorgar directly through the use of the XIII Legion’s own astropathic choirs. In the wake of the Battle of Calth, the Word Bearers Legion, led by the Primarch Lorgar, linked up with Angron and his World Eaters Legion to launch a Shadow Crusade against the Realm of Ultramar's Five Hundred Worlds in an attempt to spread the massive Warp Storm known as the Ruinstorm that had been conjured by the Word Bearers' First Chaplain Erebus at Calth across the Eastern Fringe. This prodigious Warp Storm would effectively split the galaxy in half and deny needed reinforcements to the Loyalists as Horus drove on Terra in an attempt to overthrow the Emperor of Mankind. The Shadow Crusade lay waste to 26 worlds until Guilliman's retribution fleet finally caught up to the Traitors above Angron's homeworld of Nuceria, which the World Eaters Legion were preoccupied with wiping clean of all life in vengeance for the treatment the Nucerians had merited out a century before to Angron.The XIII Legion warship Courage Above All, Guilliman's temporary flagship, broke Warp at the system’s edge, at the head of a large void armada consisting of 41 vessels. In their wrath, the Ultramarines destroyed the Word Bearers' flagship Fidelitas Lex during the furious void combat. Eventually, the Ultramarines managed to take the fight to the surface. The first Ultramarines poured forth from their Drop Pods but the World Eaters were waiting for them. The XII Legion crashed against the XIII in rabid packs, showing why Imperial forces had feared to fight alongside them for decades. Uncontrolled, unbound, unrestrained, they butchered their way through Ultramarines strongpoints, enslaved to the joy of battle because of the Butcher's Nails cortical implants sandwiched within the meat of their minds. The XVII Legion also met their enemy cousins, replacing ferocity with spite and hate. The Ultramarines returned it in kind, hungry for vengeance against the vile Traitors who had defiled Calth and damaged its star. Eventually Guilliman confronted Lorgar, and the two Primarchs came together in furious combat as their warriors killed each other around them, and neither Primarch spared their sons a glance. But in the midst of their life-and-death struggle, the Word Bearers' Primarch, Angron, intervened and confronted Guilliman. Guilliman held his own against the pair of Traitor Primarchs, but took multiple wounds for his efforts. Eventually Angron managed to plunge his Chainsword up under Guilliman’s breastplate, leaving him with a serious wound. Despite the strife raging around them, Angron still fought Guilliman, standing above the kneeling Ultramarine. Guilliman was beaten and down. His wounds bled profusely, a palette of proud defeat. Guilliman's warriors fought desperately to retrieve him. Fortunately they were granted a brief reprieve, as Lorgar's incantation locked up Angron's muscles, and began to transform the Red Angel into a new form as a Daemon Prince of Khorne. Guilliman took the opportunity to escape into his sons' defiant phalanxes, retreating in enviable unity. Lorgar saw the expression of disgusted awe on his brother's face as the wounded Ultramarine stared at the transformed Angron atop the mound of dead sons from all three bloodlines of Space Marines. The XIII Legion continued to fire even in retreat, leaving the world of Nuceria battered and bloody. Their campaign against the two Traitor Legions had ended at Nuceria...for a time.
 * c. 006.M31 Destruction of Dwell - Shortly after the infamous campaign on Istvaan V, the Sons of Horus were forced to recoup their losses. Another change, forced on the XVI Legion, was the loss of the Mournival. With the deaths of two of their former brothers, the Loyalists Garviel Loken and Tarik Torgaddon on Istvaan III, there were openings available to those that might be deemed worthy. Captain Horus Aximand approached First Captain Ezekyle Abaddon with the proposition to select two new members to fill the vacancies. They argued over who they thought would be worthy to join a newly reconstituted Mournival. After much debate, they both finally come to an accord, agreeing on suitable replacements. These would be Falkus Kibre, the commander of the Catulan Reaver Squad and Sergeant Grael Noctua. With rumours of the infamy of Horus' actions in the Istvaan System spreading across the nearby systems, a series of ferocious repercussive combats had flared through the Momed, Instar and Oqueth Sectors. The instigator was a leader of the Iron Hands Legion's "Iron Tenth", a warleader of the Sorrgol Clan named Shadrak Meduson. He had marshalled the Loyalists against the approaching Traitors of the 63rd Expeditionary Fleet. The Iron Hands warleader and his formations had come too late to stand with his Primarch Ferrus Manus at Istvaan V. He had gathered 58 full battalions of the Imperial Army about him -- warhosts from the Momed Voidhives, along with a flotilla of siege hulks from Nahan Instar, a half-broken cadre of Salamanders Astartes, some Mechanicus claves, and a White Scars raid-force rerouted from a return voyage to the Chondax war front. The world of Dwell, with its fortified cities, orbital batteries, ship schools, and eight million pinnacle-grade fighting men, would be the cornerstone of Meduson's defensive line. The Iron Hands warleader positioned himself at the Mausolytic Precinct which was situated on a high plateau overlooking Tyjun and the Sea of Enna. The Sons of Horus launched a planetary assault against Dwell, butchering the regular human Loyalist defenders, but were caught by surprise when they encountered the ad hoc Loyalist Astartes force that had secretly fortified the system. When the Sons of Horus assault units breached the fortifications, Horus Aximand slew Meduson's second-in-command, the Iron Hands Lieutenant Bion Henricos but "Little Horus" was then attacked by a White Scars kill-formation disguised as statues. Meduson's co-commander, Captain Hibou Khan of the White Scars, lead the Loyalist counterattack against the Traitors, but they were quickly driven off with the arrival of Sons of Horus reinforcements. One of the White Scars managed to gravely wound Aximand by slicing off his face. The XVI Legion's Apothecaries managed to reattach Aximand's severed face, but the muscle grafting left a wicked scar which made him look more brutal. It set the character of the face differently, altered the seating of the muscles so that his appearance now matched the growing corruption within his heart. Somehow, the wrongness, the imperfection, made him seem even more like Horus, not less.
 * c. 006.M31 Assault on Iydris - In the wake of the terrible slaughter of Loyalists at the Drop Site Massacre on Istvaan V, a small fleet of Astartes from the ravaged Iron Hands and Raven Guard Legions managed to flee off-world. Among these vessels was the Sisypheum, a Strike Cruiser commanded by the mortally wounded Iron Hands Captain Ulrach Branthan. Determined to continue to strike against the Traitor Legions wherever and whenever they could, the crew of the Sisypheum eventually manged to intercept the encoded communications of the Traitors and learned that the Traitor Primarchs Fulgrim and Perturabo were leading their Emperor's Children and Iron Warriors Traitor Legions, respectively, into the Warp Rift later named the Eye of Terror by Perturabo in search of an unknown Eldar weapon known as the Angel Exterminatus which could decisively tip the balance of the Horus Heresy in favour of the Traitors. The Iron Hands eventually assembled a small fleet of similar Loyalist survivors of the Drop Site Massacre and made their way into the Eye to stop the Traitors from acquiring this weapon. Once within the Eye, Fulgrim led the combined Traitor Legion forces to the ancient Eldar Crone World of Iydris, into the citadel known as Amon ny-shak Kaelis where the Angel Exterminatus was supposedly located. The Traitors were forced to repel countless attacks by the ancient Eldar defense systems and by attacks from Eldar constructs animated by the ountless dead Eldar souls of the Crone World. In truth, the entire quest for the Angel Exterminatus had been a ruse perpetrated upon Perturabo and the Iron Warriors by Fulgrim and the Emperor's Children. Fulgrim, now a Champion of the Chaos God of Pleasure, Slaanesh, sought apoetheosis to become a Daemon Prince of the Prince of Chaos. But he needed the power provided by the life force of a Primarch and the sacred energies of a place like an Eldar Crone World that was sacred to Slaanesh to complete his ascension to daemonhood. Fulgrim had given to Perturabo a cloak, to which was affixed a skull-shaped pin carrying a relic known as a maugetar stone. As long as Perturabo was within the confines of the Eldar citadel the stone slowly absorbed his life force and fed these energies to Fulgrim. Once Perturabo discovered his brother's perfidy, the Iron Warriors launched an assault upon the Emperor's Children, and a three-way battle soon developed as the Iron Hands from the Sisypheum and its small flotilla of Loyalists entered the fray against both Traitor forces, unaware of what was truly happening. In the course of the combat that followed, Perturabo slew Fulgrim's mortal body with the great warhammer Forgebreaker, which ironically had originally been forged for Fulgrim by Ferrus Manus. But this action was only the final component in Fulgrim's ritual of apoetheosis, and his body remade itself into the twisted, serpentine form of a Slaaneshi Daemon Prince. Fulgrim became the first of the Traitor Primarchs to ascend to daemonhood, but he would not be the last. His goal achieved, Fulgrim had teleported his Emperor's Children away from Iydris and the Crone World began to collapse as the potent life forces of the dead that had long sustained it were drained away by Fulgrim's ascension. The Iron Hands and Perturabo's Iron Warriors successfully fled the crumbling planet, though Perturabo escaped by taking his fleet deeper into the black hole that lay at the centre of the Eye of Terror. For the first time, one of the Traitor Legions had turned on another, a situation that was to become all too common as the Dark Gods of Chaos tightened their grip on Horus' followers.
 * c. 009.M31 Battle of Tallarn - To this day the largest tank battle ever conducted in Imperial history remains the Battle of Tallarn. During the Horus Heresy, the Iron Warriors Traitor Legion launched a massive assault on the world of Tallarn. To soften up the Loyalist resistance, the Iron Warriors virus-bombed the former Agri-world, and the Life-Eater virus turned the once lush and productive breadbasket world into a wasteland of endless desert in short order. The few surviving Imperial citizens emerged from underground shelters to oppose the Iron Warriors' attack and soon reinforcements landed on the Desert World for both sides. Elements from the Iron Hands and Imperial Fists Legions arrived to oppose the invasion but the now-hazardous environment forced both sides to fight within the environment-sealed confines of their battle tanks. Both the Loyalists and Traitors committed armoured fighting vehicles of all sizes and configurations to the conflict in numbers never before seen in a single battle. The resulting fighting was fierce and merciless with both sides taking horrendous casualties. Eventually the Iron Warriors were forced from the planet by the Loyalist counter-attack. In the aftermath of the fighting, over a million wrecked tanks littered the surface of Tallarn, rusting in the endless dunes and wasting sands of the devastated planet. The ruination of Tallarn is a slight against the Imperium the Iron Hands and Imperial Fists have never forgotten. It was not until many centuries later that the people of Tallarn learned to their horror why the Iron Warriors had invaded their world—they had come seeking the Cursus of Alganar, an ancient Chaotic artefact that acted as a gateway into the Realm of Chaos within the Warp.
 * c. 012.M31 Siege of Lesser Damantyne - Commanding the 51st Expeditionary Fleet, Warsmith Barabas Dantioch led a large Iron Warriors detachment in bringing the world of Lesser Damantyne into Imperial Compliance. The Warsmith would later be laid low during a massive Hrud infestation on the world of Gholghis which left him prematurely aged and crippled by the attack of those foul xenos. Warsmith Dantioch left the 51st Expedition to garrison the world of Lesser Damantyne, becoming the planner and architect of the superbly fortified Schadenhold fortress. During the many months the small Iron Warriors detachment had garrisoned the planet, they heard disturbing rumours of the galaxy being conquered by the Traitor forces of the Warmaster Horus. Dantioch suspected that the bulk of the IV Legion had willingly joined the Warmaster's cause. When Warsmith Krendl arrived at Lesser Damantyne with the 51st Expeditionary Fleet, he came to the Schadenhold with new orders for the Iron Warriors garrison. They were ordered by their Primarch to prepare for the Traitors' offensive against Terra. Lesser Damantyne would be used as a resupply point for Horus' forces. Dantioch refused to acquiesce to his Primarch's orders for the Iron Warriors on Lesser Damantyne remained Loyalists and would not share in their traitorous brethren's damnation. Krendl vowed to destroy Dantioch's beloved fortress in the name of Horus. Dantioch commanded his meagre forces against the entire might of the 51st Expeditionary Fleet and the 14th Grand Company of the Iron Warriors for 366 standard days, until the Traitors deployed an Imperator-class Titan to destroy the Schadenhold. Just before the fortress fell, Dantioch and the surviving Loyalist Iron Warriors teleported aboard the Traitor's flagship and commandeered it. The Warsmith then set course towards Terra with the aim of helping to fortify and defend the Emperor's Imperial Palace against the forces of the Traitor Legions. Dantioch's ultimate fate remains unrecorded in Imperial records at this time.
 * c. 014.M31 Battle of Terra - As the events of the Horus Heresy neared their tragic conclusion seven years after the fateful betrayal at Istvaan III, those Loyalist Legions not committed to the defence of Terra raced through the Warp, converging on the homeworld of Mankind. The Traitor Legions also massed above Terra to assault the Imperial Palace. The Battle of Terra was the final confrontation of the Horus Heresy that raged on Terra itself between the Forces of Chaos led by the Warmaster Horus and the Loyalist armies of the Imperium of Man led by the Emperor of Mankind himself. The Loyalist forces ultimately proved victorious in their defence of the Imperial Palace, though only just barely, and Horus was ultimately slain by the full psychic powers unleashed by the Emperor on the deck of his massive Battle Barge the Vengeful Spirit, though the Master of Mankind was mortally wounded and had to be interred within the cybernetic life support mechanisms of the advanced psychic augmentation technology known as the Golden Throne. The outcome of the Battle of Terra shaped the destiny of humanity for the next 10,000 standard years. The Traitor hosts began their fighting withdrawal, and in the anarchy and confusion Horus' body was recovered by his Legion from his flagship. Having fought their way clear of the Sol System the XVI Legion fled for the Eye of Terror where the Sons of Horus established a world that was at once the tomb of their lost Primarch and a fortress from which they would launch further attacks both upon their fellow Traitor Legions and against the smouldering Imperium. Thus began the Long War of the Forces of Chaos to overthrow the "Corpse Emperor." With Horus slain, First Captain Ezekyle Abaddon emerged as the Warmaster's heir, commanding both the Sons of Horus and what remained of the splintering Forces of Chaos. Soon known as Abaddon the Despoiler, he renames the Sons of Horus the "Black Legion" and declares himself the new Warmaster of Chaos Undivided. Highly favoured by the Chaos Gods, Abaddon intends to complete the task begun by Horus and see the Emperor slain and the Imperium ground beneath the boots of the XVI Legion.
 * c. 014-021.M31 The Great Scouring - Traitor forces throughout the galaxy are quelled by the Imperial Loyalists of the Adeptus Astartes and the Imperial Army or forced to retreat from Imperial territory they captured under Horus' leadership in a campaign that becomes known to Imperial history as the Great Scouring. The Forces of Chaos, including the Chaos Space Marine Traitor Legions, Traitor Imperial Army units, the forces of the Dark Mechanicus and the Traitor Titan Legions, all retreat into the vast Warp rift called the Eye of Terror.
 * Unknown Date.M31 Battle of Skalathrax - On the Daemon World of Skalathrax in the Eye of Terror, shortly after the Horus Heresy, the World Eaters and the Emperor's Children fought. Amid the World Eaters was the Champion of Khorne named Khârn. After a full day of vicious fighting in what would become known as the infamous Battle of Skalathrax, the terriblly frigid Skalathrax night began. Horrified, Emperor's Children and World Eaters alike ran to their shelters, for the freezing night would kill even a Chaos Space Marine in a matter of moments. Khârn raged over being delayed from slaughter for even a single night. Filled with anger when he saw that his brother Chaos Marines were creeping back to the shelters, he took up a flamer and burned them down, slaying with his chainaxe Gorechild any who tried to stop him. The night was filled with the screams of the dying and the freezing as Khârn strode the streets of the dead city of black stone, killing Emperor's Children and World Eaters alike, burning any shelters he found. The night was lit by flames as the Emperor's Children and the World Eaters fought each other and themselves for the few remaining shelters. By morning, most of the World Eaters were dead, the survivors split into small warbands, the shattered remnants of the once great Companies of the Legion. The Legion would never reunite and would remain scattered in warbands for the next ten millennia.
 * Unknown Date.M31 Battle of Eskrador - After the death of Horus at the end of the Horus Heresy during the Great Scouring, the Alpha Legion and the Ultramarines Legion met in battle on the world of Eskrador, where Roboute Guilliman faced his hated brother Primarch in bitterly contested close combat. Both struck one another in an instant, each power sword making a single stroke. For a second the two Primarchs stood facing one another, than Alpharius slumped to the ground. Exalted by their Primarch's victory the Ultramarines renewed their attack and cut down every last Alpha Legionnaire. But their exaltation was short lived, as over the next few days the Ultramarines were harried from all sides by the Eskandor natives as well as remnants of Alpha Legionnaires hiding throughout the mountains. After another week of futile combat against their shadowy opponents, Guilliman ordered his Ultramarines to evacuate the planet's surface. He then used his Legion's ships to bombard the traitors from orbit. Despite Guilliman's protests that he had no wish to fight such dishonourable foes, it seems hard to dispute the fact that the Ultramarines were soundly beaten by the Alpha Legion at every turn, despite the loss of Alpharius.
 * Unknown Date.M31 Eastern Fringe Genocide - Following the death of Horus during the Battle of Terra, the Traitor Legions were driven into the Eye of Terror. Unlike the other Traitor Legions, after their defeat in the Thramas Crisade, the Night Lords did not splinter into separate warbands and flee like the rest of their fellow Traitors. Instead, the Night Lords conducted a massive campaign of genocide and terror against the Imperium across the Eastern Fringe of the galaxy, the likes of which has never been seen before, or since. The Legion betrays the growth of the increasing sense of self-destruction which drives its Astartes, much as it drives their Primarch. The Night Lords' rampage is only stopped by the assassination of Konrad Curze at the hands of the Callidus Assassin M'Shen.
 * Unknown Date.M31 Fall of Caliban - In the aftermath of the Horus Heresy, the surviving Loyalists rallied the reeling Imperium. The Dark Angels took a significant part in these battles, which later came to be called the Great Scouring. As they pursued the rebels, the I Legion diverted to nearby Caliban, which had been enshrouded by Warp Storms since Horus' betrayal. For Lion El'Jonson, one final act of treachery remained to be discovered. Upon the Dark Angels' arrival in orbit, they were fired upon from the surface. Pulling back the Legion fleet, El'Jonson tried to find out what had happened, and discovered that Luther -- who had become embittered by what he perceived as El'Jonson always taking all the glory -- had poisoned the minds of the Dark Angels garrison and the new recruits that had been left on the planet against their Primarch. Correctly believing that Luther and the planet-side Dark Angels had actually been tainted by Chaos, an infuriated Jonson ordered that Caliban be bombarded from orbit, destroying the planet's defences. El'Jonson then led his forces to the surface and assaulted the Order's fortress-monastery, where he confronted Luther in single combat. Luther, transformed into a Chaos Champion by the power of the Chaos Gods, was now evenly matched in strength with the enraged Primarch. The battle between the two levelled the Order's fortress-monastery as the planet was coming apart around them, the orbital bombardment taking a heavy toll on the surface. El'Jonson managed to wound Luther, but could not bring himself to kill the man who had been his brother and mentor. Luther lashed out with a powerful sorcerous attack that mortally wounded the Primarch. As he saw what he had done, Luther felt a veil lift from his eyes, and the Chaos Gods -- seeing that once again their chosen Champion had failed to defeat the lackeys of the Emperor of Mankind -- lashed out with the powers of the Warp. The Fallen Angels were scattered throughout space and time, and Caliban tore itself apart under the strain of the Ruinous Powers' assault. The only portion of the planet remaining intact was the rock on which stood the fortress-monastery in which Luther and the Lion had duelled. The Dark Angels entered the shattered monastery and captured the broken Luther; of El'Jonson himself, however, there was no sign. It was believed that Jonson was thrown into the maelstrom of space and time by the Chaos Gods along with the Fallen. The truth was that the Lion still lived, though he had been placed into a coma and had reemerged into realspace with the aid of the Watchers in the Dark in a secret chamber deep beneath the fortress-monastery which even his brethren did not know existed. Only the Emperor of Mankind, sitting silent on the Golden Throne from which he sees all, and the Watchers themselves, know this greatest secret of the Dark Angels. Even the Supreme Grand Master of the Chapter is not privy to this truth. However, legends soon spread throughout the Chapter that the Lion would find his way back to the Dark Angels on that grim day when they went to war in defence of the Imperium for the final time.
 * Unknown Date.M31 Battle of the Iron Cage - Upon the world of Sebastus IV the traitorous Iron Warriors, bitter archenemies of the Imperial Fists, laid an ingenious trap to ensnare Rogal Dorn and his Legion. Heedless of the inherent danger, the Primarch ordered the Imperial Fists to attack the Iron Warriors' Eternal Fortress -- later referred to as the "Iron Cage" by the surviving Astartes of the VII Legion. The battle should have favoured the treacherous trench-fighters of the Iron Warriors, but the Imperial Fists endured. For all their skill and ferocity, as devotees of Chaos, the Iron Warriors lacked the faith required to make the ultimate sacrifice that victory -- and the Ruinous Powers -- demanded. While they paused, the Ultramarines Legion intervened; Roboute Guilliman had decided that Perturabo's destruction was not worth the loss of Rogal Dorn and had brought his Astartes to drive off the Iron Warriors
 * Unknown Date.M31 First Battle of Garm - In the aftermath of the Horus Heresy, the Thousand Sons attacked the Space Wolves' Shrine World of Garm, which was named for a famous Wolf Lord from the earliest days of the Space Wolves Legion who had given his life defending the Primarch Leman Russ from an attack by Magnus the Red. Leman Russ raised a cairn to Garm upon the place of his death and placed the Spear of Russ, the mighty weapon gifted to him by the Emperor Himself which had wounded the Traitor Magnus, atop Garm's tomb. The Space Wolves were able to fight off the Thousand Sons Traitor Legion and drive them from the world.
 * c. 021.M31 The Codex Astartes is completed - The Ultramarines Primarch Roboute Guilliman completes his Codex Astartes, a volume which lays down the new organizational and tactical doctrines for existing and future Loyalist Space Marine Chapters.
 * c. 021.M31 The Second Founding - The remaining Loyalist Space Marine Legions are broken into Chapters comprised of only 1,000 warriors each so that one man may never again command the full power of an entire Legion of Astartes. Twenty-three new Space Marine Chapters are created in this manner, whilst the 9 existing Loyalist Legions are reshaped into smaller Chapters that continue to bear the original names of their Legions. The Grey Knights, a special Space Marine Chapter comprised entirely of psykers that will eventually evolve into the Chamber Militant of the Ordo Malleus of the Inquisition, is secretly created by Malcador the Sigillite, the Regent of Terra and chief aide of the Emperor, on the moon of Saturn called Titan, which serves as the eventual headquarters for the Ordo Malleus, the branch of the Inquisition dedicated to protecting the people of the Imperium from the daemonic forces and temptations of Chaos. The newborn Inquisition takes as its eventual symbol Malcador's personal sigil.
 * c. 084.M31 Disappearance of Jaghatai Khan - The White Scars' Primarch Jaghatai Khan disappears while fighting several Kabals of the Dark Eldar on the world of Corusil V, near the Warp rift called the Maelstrom. Presumably he pursued a Dark Eldar lord through an alien portal that led into a portion of the Eldar Webway occupied by the Dark Eldar, perhaps even reaching their Dark City of Commorragh.
 * 120.M31 Dark Angels Search for Recruiting Worlds - Necessity demands that the Dark Angels find a new recruiting world after the destruction of Caliban, but at this date, a conscious decision is made instead by the Chapter to establish many. This plan is agreed to by the High Lords of Terra as it allows for contingencies and preserves the Chapter's genetic diversity. For the Dark Angels, it allows the preservation of a mantle of secrecy, for no one is entirely sure of the number of the Chapter's recruiting worlds or of how many Aspirants are taken into The Rock.
 * c. Early to Mid-M31 - In the aftermath of the Horus Heresy, countless prophets and visionaries preach the Emperor is, and always has been, the one, true God of Mankind. The most influential of these cults of Emeperor-worship is the Temple of the Saviour Emperor, whose doctrine will eventually be adopted as the orthodox theology of the Imperial Cult centuries later.
 * 580.M31 - 632.M32 The Forgotten Wars - Rumours lead the Dark Angels, with two of their Unforgiven Successor Chapters, to embark upon a harrowing campaign. In hindsight it is easy to see that the Ruinous Powers baited the Dark Angels, luring them into the swirling edge of the Eye of Terror. Only the Dark Angels' irrepressible resolve allows them to escape, and they pay a high price in casualties.
 * c. 781.M31 The 1st Black Crusade Begins - Abaddon the Despoiler, the self-appointed heir of Horus and the new Warmaster of Chaos Undivided after Horus' death, makes his first attempt to launch a new offensive against the Imperium of Man following the Horus Heresy when his forces initiate the First Battle of Cadia. This attempt fails and the Forces of Chaos are unable to penetrate the Cadian Gate that will allow them to take control of the only truly navigable pathway out of the Eye of Terror and into Imperial space. For the next 10,000 standard years, Abaddon will bend all of his efforts to finding a way to complete what Horus began and launch a Chaotic war that will conquer Terra and eliminate the Corpse Emperor. These massive assaults become known as "Black Crusades" to the people of the Imperium.