Chaos Space Marines

"Death to the False Emperor! Death to the weakling Imperium of Mankind!"

- Oath of the Traitor Legions

A Chaos Space Marine, also sometimes called a Traitor Marine or a Renegade Marine, is a former Loyalist Space Marine of the Imperium of Man who has chosen to betray the service of the Emperor of Mankind and dedicate his soul to the service of Chaos and its foul deities. Such corrupt Astartes normally belong to one of the 9 Traitor Legions that betrayed the Emperor during the ancient civil war called the Horus Heresy more than 10,000 standard years ago, while others come from Space Marine Chapters created long after the Heresy ended that have turned Renegade. Chaos can corrupt Astartes of any time and place just as its siren call leads many lesser men to their damnation.

During the Horus Heresy, the terrible Imperial civil war that pitted the Battle-Brothers of the 18 known Space Marine Legions against one another, there were two factions. These were the Loyalist Space Marines who continued to serve the Imperium and the Emperor of Mankind and the Chaos Space Marines of the Traitor Legions who betrayed the Emperor's trust and pledged their souls to the dark service of the 4 Ruinous Powers of Chaos. Some Traitor Marines pledged their service to all 4 of the Dark Gods, a force known as Chaos Undivided, whilst others preferred to dedicate themselves to the worship of only a single one of the Ruinous Powers. The Traitor Legions were led by the Warmaster Horus, once a Primarch of the Imperium and the Emperor's most trusted friend, son, and adviser before he was corrupted by the promises and lies of the Dark Gods and his own inner flaws.

The Traitor Legions were the most powerful component of the Forces of Chaos which fought during the Heresy, which also included the myriad daemons of the Warp, human Traitors from the Imperial Army, the Dark Mechanicus and Chaos Cultists drawn from across the galaxy. The flesh and Power Armour of Chaos Space Marines often warps and twists into new, darker and inhuman forms under the influence of the Chaos energies they are exposed to as their shapes morph to embody the corrupted Astartes' new allegiance. Chaos Space Marines fight for everything they were once forbidden to indulge in as the ascetic servants of the Emperor and the selfless guardians of Mankind. Pleasure, wealth, but above all else the power to rule their fellow men in the name of the Chaos Gods, is the driving ambition and goal of every Chaos Space Marine.

History
The Traitor Legions of the Chaos Space Marines represent 9 of the 20 original First Founding Legions of Space Marines who were created by the Emperor of Mankind from the genomes of his 20 Primarchs in the late 30th Millennium to fight the Great Crusade that forged the Imperium of Man. At this time Horus, the Warmaster of the Imperial forces and Primarch of the XVI Legion, the Luna Wolves, (which the Emperor allowed him to rename the Sons of Horus in his honour before the onset of the Horus Heresy to demonstrate his status as first-among-equals among the other Primarchs), was corrupted by Chaos and instigated the galaxy-wide Imperial civil war known as the Horus Heresy in his determination to replace the rule of the Emperor with his own.

After the death of Horus at the hands of the Emperor aboard his Battle Barge Vengeful Spirit during the Battle of Terra that ended the Horus Heresy, the remnants of the 9 Traitor Legions fled, along with the other Traitor Imperial forces that now served Chaos, into an area of the galaxy where the Warp bled into realspace, creating the permanent Warp Storm known as the Eye of Terror. Due to the nature of Chaos, and the temporal instability of the Warp, many of the very same Chaos Space Marines who revolted against the Emperor more than 10 millennia ago continue to fight against the Imperium today, having effectively been granted a tortured immortality by the will of the Ruinous Powers.

The Traitor Legions have kept their old names, with the exception of the Sons of Horus who were renamed the Black Legion by their new leader, Abaddon the Despoiler, once Horus' chief lieutenant and the First Captain of the Luna Wolves before he followed Horus into damnation. Besides Horus, 2 other Traitor Primarchs were killed during or shortly after the Heresy (Alpharius of the Alpha Legion and Konrad Curze of the Night Lords). The 6 surviving Traitor Primarchs have since been transformed into Daemon Princes by the Chaos Gods they serve. These daemonic Primarchs rarely take part in the affairs of their Legions or are major players in the affairs of the galaxy. Four of the Traitor Legions have pledged a singular loyalty to one of the great Chaos Gods. while the others serve the interests of Chaos as a whole in the form of Chaos Undivided. Due to the nature of Chaos and those who choose to serve it, not long after the end of the Heresy the Traitor Legions, save for the Word Bearers, largely stopped operating as unified military organisation and instead devolved into a series of separate and often competing warbands. The Traitor Marines who command these warbands, all potent Chaos Champions, sought their own personal glorification and the eventual opportunity to become Daemon Princes in their own right by earning victories in the cause of Chaos.

Due to the fractious nature of the Dark Gods, the warbands in service to a particular Ruinous Power often view other Traitor Marine warbands who serve its patron's rival deity as even more appropriate targets for their wrath than the servants of the Emperor. With such an attitude prevailing among the corrupted Astartes, it has often proven impossible for the Traitor Legions to present a united front against the Imperium since the death of Horus, which is one reason why they have never enjoyed a similar series of military successes over the past 10 millennia. The closest thing to unity that has appeared amongst the Traitor Legions and other Chaos Space Marines was when Abaddon the Despoiler, the successor of Horus as the Warmaster of the Black Legion, launched one of his periodic Black Crusades into Imperial space under the banner of Chaos Undivided, which is a temporary period of unity amongst all the Forces of Chaos when they seek to overwhelm the Imperium's defenses surrounding the Eye of Terror and drive on Terra once more. Abaddon is the only Champion of Chaos since Horus himself who is able to command, however begrudgingly and briefly, the loyalty of all 9 Traitor Legions, and he has led 13 Black Crusades out of the Eye of Terror against the Imperium of Man. The latest, the 13th Black Crusade, was launched in 999.M41 and has proven the most successful for the Forces of Chaos since the Horus Heresy. The Chaotic troops were able to seize a foothold on the surface of the Fortress World of Cadia, though the Imperial Navy has so far managed to blockade Abaddon's Traitor Marines and the other Forces of Chaos from breaking out into the Cadian Gate, the only clear pathway through the Warp from the Eye of Terror into open Imperial space. Should the Chaotics manage to eventually break out of the Imperial Navy's stranglehold, the Chaos Space Marines may at last, after 10,000 years, bring down the realm of the Corpse Emperor and gain their vengeance for long millennia of exile. Then the galaxy will tremble as the servants of the Dark Gods at last throw down the Corpse Emperor and claim the souls of Mankind for their own.

Chaos and Loyalist Space Marine Differences
"Rejoice brothers! Your slavery to the false Emperor ends today!"

- Chaos Lord Araghast the Pillager

All men of power can choose to devote their lives to the pursuit of great good or great harm to others, and the Space Marines are no different from other mortals in this respect. Genetically engineered as an adolescent to be a superhuman warrior, and armed and armoured with the Imperium's most advanced technology, a Space Marine is intended to serve as the ultimate defender of Mankind. Not only is his body protected against the weapons of his foes, but his mind has been toughened through the use of potent psycho-conditioning and indoctrination methods to expunge all fear, pain and temptation. To become an Astartes is to surrender one's own life and aspirations to the service of the Emperor and Mankind, and to wholly dedicate oneself to this singular purpose forever more. Those who live secure behind the shield of valour created by the Space Marines can never truly understand the true enormity of the sacrifice that the Astartes have made for their fellow men -- for they have sacrificed their own humanity in service of those they have sworn to protect.

When an Astartes falls from grace, he will fall further than other mortals. A lifetime dedicated to self-deprivation and selflessness is simply thrown aside and the Space Marine indulges his newfound independence in thought and deed to its fullest extent. Freed from the constraints of the discipline, traditions and responsibilities that define the Adeptus Astartes, a Chaos Space Marine can exercise his every whim, whether it be for bloodshed, mayhem, sensual pleasures long denied, ambition, love or simple vengeance. Given full reign to his long-supressed personal desires, his incredible physical powers and mental strength can be turned to the pursuit of the most malevolent acts, untrammeled by any sense of either mercy or guilt. When an Astartes' will finally breaks, the result is catastrophic as the whole edifice of his purpose and psyche tumble into an often violent maelstrom of unleashed and pent-up desire.

Having been created for combat, most Chaos Space Marines first turn to the only thing they have ever known -- the pursuit of war. Though their ideals and goals may have been cast aside, their superhuman bodies and tactical and strategic skills remain intact. Released from the confines of the need to follow orders and pursue missions prescribed by others, a Chaos Space Marine can become a cold and psychopathic killer without morals or restraint. He pursues this bloody life to its fullest extent, glorifying in the power of his genetically enhanced body and the ability it renders him to unleash death and misery upon those he once served.

Some Chaos Space Marines never grow past this point and remain bloodthirsty Renegades, corsairs and pirates for the rest of their long lives. Others, now free to explore the temptations of the galaxy all around them, reach out in all direction to widen their mental horizons and experiences. Once a subservient cog within their Legion or Chapter's machinery dedicated to the service of a distant Emperor, a Chaos Space Marine may come to relish the chance to be a master rather than a servant, enslaving nations and whole worlds into the service of himself and the Ruinous Powers. Others prefer to pursue different avenues, such as the study of once-illicit texts or a passion for technical or sorcerous knowledge forbidden to the servants of the Imperium. Some Chaos Space Marines prefer to inflict pleasure and pain upon themselves, pushing their bodies and minds to the limits of what they can withstand and beyond, desperate for a sensual reward that mortals, even Astartes, were never intended to experience.

To be a Chaos Space Marine is ultimately to feel a near god-like power over other beings, particularly one's fellow men. Having been freed for decades, if not centuries, from the experience of fear and now released from responsibility, a Chaos Space Marine does not dread either retribution or punishment for his deeds. For most Chaos Space Marines, all memories of their heroic pasts are soon lost amidst the rivers of blood and the ecstacies of new sensation, and any thoughts of the future are but half-imagined cravings for more... more power, more killing, more pleasure, more pain.

By dedicating himself body and soul to the Dark Gods, an Astartes not only finds a patron who approves and encourages his new life, but who will actually reward him the further down that path he walks. For one whose sole existence was once defined by the necessity of self-denial and utter obedience, the euphoria of this realisation of true freedom can be an even more potent intoxicant than the pride he once felt at being accepted as one of the Emperor's Space Marines.

It is this temptation that constantly beckons to all Loyalist Space Marines. They cannot claim to be ignorant of its existence, as the teachings of their Chapter and its Chaplains remind them daily of both their purpose and their duties. No Space Marine casually walks away from these once-welcome bonds, no matter what might occur in his life. For an Astartes to turn to the service of Chaos he must consciously make the choice to walk a radically different path, to choose profane freedom over righteous service. Once made, it is a decision that can never be recanted, for from the moment that a Space Marine renounces his service to the Emperor, he is truly lost and irrevocably damned.

The Chaos Space Marines have the same genetic origins as the Space Marines in the gene-seed created by the Emperor from the genomes of the 20 Primarchs, and thus have the same physical abilities as their uncorrupted counterparts. Due to their allegiance to Chaos, Veteran Chaos Space Marines often suffer from extreme mutations (or Chaotic "gifts" depending on the point of view). Traitor Marines are virtually immortal due to their sojourns within the Warp, and their millennia of experience afford them levels of tactical mastery and advanced battlefield skills that the much younger Loyalist Space Marines have not yet earned.

Chaos Space Marines are equipped with the ancient patterns of Power Armour and weapons they had when they initially betrayed the Imperium at the start of the Horus Heresy, which are broadly the same as those used by the current Loyalist Space Marines (although some differences now exist with regard to Jump Packs, Power Armour appearance, etc). At present in the late 41st Millennium, some 10,000 standard years after the Horus Heresy, the Imperium of Man has made a few, mostly minuscule technological advancements, due to the recovery of certain Standard Template Construct (STC) technologies from the interstellar human civilisation that existed during the Dark Age of Technology, though in most ways the Imperium has either completely stagnated or even regressed from the technological level prevalent across the Imperium during the Great Crusade in the early 31st Millennium. Chaos Space Marines have far more limited access to the handful of new inventions that have appeared on the galactic scene in the last 10,000 years. In general, anything developed since the Heresy is unavailable to the Traitor Marines unless it has been captured or was already deployed among Space Marines who went Renegade in more recent centuries; for example, the Iron Warriors Traitor Legion is well-known for capturing and using more modern patterns of Imperial tanks and armoured vehicles. While Chaos Space Marines may possess older technology than their Loyalist counterparts, they compensate for this weakness through the ability to summon daemons from the Immaterium and make use of daemonic technology like daemon engines, as well as the unbridled power of arcane sorcery drawn from the Warp without fears of limitation or corruption.

Because the Chaos Space Marines have all dedicated their souls to Chaos, they are extremely fearful of death, knowing that their souls will ultimately be consumed by the Ruinous Powers, unless they can earn the rare promotion to become Daemon Princes in their own right. The Chaos Gods do not truly care for their Chaos Space Marine servants, any more than they do for any mortals who serve them. The Dark Gods would gladly see them tortured for all eternity within their realms in the Immaterium simply for their own pleasure. Worshipers of Khorne are cursed to feel eternal rage but denied the ability to slaughter, the children of Nurgle are forever consumed by despair and the wracking pains of a hideous death, those who serve Slaanesh as their patron will be tortured for the sheer pleasure of the Prince of Chaos until the end of time, and the servants of Tzeentch know only endless insanity as their souls constantly change in form and the knowledge of the universe they crave is forever placed just out of their reach. In theory, those souls who choose to serve Chaos Undivided are either shared or fought over by the Chaos Gods in the afterlife of the Immaterium.

Only the promise of eternal life as a Daemon Prince, a dubious honour earned through unbridled success in the service of Chaos, reassures those mortals who pledge their lives and souls to Chaos. This fear of death, however, does nothing to slow or halt the vicious might of the Chaos Space Marines, who are quite sure that the power they have received from the Chaos Gods in return for their souls will ultimately provide them with rule over their fellow men, as is the right of every Astartes. It will also provide the opportunity to earn the necessary glories required to appease the Dark Gods and claim the daemonic immortality they offer as ultimate reward.

Champions of Chaos
In the Immaterium, similar thoughts and emotions of the sentient beings of the galaxy join together like rivulets of water running down a cliffside. They form streams and flows of anguish and desire, pools of hatred and oceans of pride. For billions of standard years these tides and waves of psychic energy have flowed unceasingly through the Warp and such is their power that they eventually formed creatures hewed from the energy of the Empyrean. These instinctual, formless entities eventually gained rudimentary consciousness and the Chaos Gods were born -- great psychic presences composed of the best dreams and worst nightmares of the galaxy's mortals. As the sentient races of the galaxy prospered and grew, their hopes and dreams, their rage and conflicts and their loves and hatreds, all fed the growth of the Chaos Gods and nurtured their power. Eventually, the gods reached into the dreams of mortals to demand both their praise and their service.

A Chaos God can only increase its power through the collective actions and thoughts of the galaxy's mortals, regardless of their species of origin. Those who worship a Chaos God and behave in a way that feeds its psychic nature are rewarded with strange gifts, mutations, extraordinary psychic powers and potentially the greatest reward -- ascension as an immortal Daemon Prince. As the Chaos Gods battle one another within the Warp and the Realm of Chaos, so to do their followers wage war upon one another in the material universe. The victors of these battles earn more power for their masters, although the machinations and natures of the Chaos Gods are such that often a victory is unnecessary, merely the acts of sacrifice and battle in and of themselves.

When the devotees of Chaos die, their psychic energy, their souls in the Warp, do not fade away to an unknown destination, are not destroyed and are not devoured by daemons like the souls of others. Instead their souls are swallowed by the collective power of the gods, sustaining them and increasing the eternal power of Chaos.

Although untold billions of sentients worship the Chaos Gods under a myriad of different guises, names and aspects, for the majority of those who serve Chaos, the Dark Gods offer simply the chance for more power and wealth in a universe where such things are rarely easily attained. But there are those few men and women who dedicate their lives to becoming true warriors of the Chaos Gods. For these devotees, the allure of Chaos is even stronger. The Champions of Chaos have a deep, fervent belief in the Ruinous Powers and their committment is total: they swear themselves body and soul, in this life and beyond, to Chaos.

Those who dedicate themselves to the service of Chaos are doomed to an all-or-nothing existence as Chaos Champions in the service of one of the Dark Gods, or even of Chaos Undivided. The reward for those who please their god is ultimate power; for those who fail it is only eternal oblivion. To achieve greatness in the eyes of their god, Chaos Champions will perform any act, no matter how immoral, insane or vile. A Champion of Chaos does not simply praise and venerate the Chaos Gods, he swears his life and soul to their service, bargaining away his own essence in exchange for power and the rewards of their patronage. Granted the forbidden knowledge and strength of Chaos, a Champion can lead armies, conquer whole worlds and achieve greatness and ultimately, immortality. At the same time, the gods who choose to favour this Champion can bring their influence to bear upon him, so that even as he furthers his own ambitions, he also furthers the dominance and plots of his patrons. Chaos Champions are the leaders of the Forces of Chaos and the majority of them are Chaos Space Marines, though some have far more mundane origins. It is a great irony that the same abilities that make Space Marines the greatest defenders of the Imperium are also extraordinary assets for those who would become the most potent warriors of the Chaos Gods.

The genetic alterations that create a Space Marine also make Astartes more resistant to the mutational affects of exposure to the energies of Chaos, which allows a Chaos Space Marine to better survive the attentions of his often-capricious new patrons. Just as their bodies benefit from the changes wrought upon them by the ancient technologies pioneered by the Emperor, so too are the minds of Space Marines honed to an incredible focus and possessed of a potent force of will. These are qualities that stand a man in great stead if he wishes to become a Chaos Champion. Those who lack a certain clarity of thought, the mental steel required to be successful, will soon be engulfed and lost in the constant anarchy of service to Chaos or will be swiftly overthrown and slain by more ambitious and ruthless subordinates and comrades. Chaos cares little for loyalty -- power is given to those strong enough to claim its rewards.

Chaos Space Marine Warbands
Save for a few Champions dedicated to the most pure service of Khorne, Chaos Champions do not live and fight alone. Other followers of Chaos are drawn to them, either through the will of the gods or through the draw of a Champion's own glory and reputation. These groups form the warbands of Chaos and they can vary in size from a handful of individuals to massive hosts that rival an Imperial Guard regiment in size and power. The most successful Chaos Champions command vast armies of devoted warriors. For Chaos Space Marines these warbands are mostly composed of comrades they fought alongside in their Traitor Legions or their Renegade Chapter. Yet it is not uncommon for Renegades with very different histories to find a common cause in their service to the Ruinous Powers, as Chaos recognises neither hierarchy nor structure, only results.

These warbands compete with each other as much as they fight against xenos and the forces of the Imperium. Resources are precious and hard-won in the Eye of Terror and the Maelstrom and control of cities, continents and worlds is vital to the maintenance of power. Most valued over all other things is the favour of the Chaos Gods. Champions and their warbands must constantly prove their continued dedication to their patrons. The Chaos Gods are embodiments of the question: what have you done for me lately?

Champions earn rewards from their gods by destroying their patron's enemies and succeeding on obscure missions and quests. On the Daemon Worlds in the Eye of Terror, hundreds of warbands struggle in battle to best each other for possession of daemonic artefacts, ancient knowledge, weapons and war machines left over from the days of the Horus Heresy and from before the Fall of the Eldar. They are pitched into eternal conflict as sacrifices to their gods and to earn the power to summon daemons to their cause. When not battling one another, the warbands of Chaos Space Marines are a roving threat, for they are wandering bands of nomadic warriors intent only on slaughter and loot. From bases hidden in asteroid fields and upon the surfaces of deserted moons, aboard painstakingly maintained starships that date back to the Great Crusade, they watch and wait for their prey to appear, gathering strength wherever a new blow can be struck against the despised Imperium of Man and its hated Corpse Emperor.

Ascension
In the end, every Chaos Champion faces one of three fates. A life of constant warfare is a dangerous one and most will die upon the field of battle, forgotten by their god as just another failure but immortalised in legend by their remaining followers and comrades. These Champions are nothing more than blood-soaked sacrifices to Chaos, their goals and ambitions forever unfulfilled.

A Chaos Champion who survives the constant battles will slowly gain more and more favour from his chosen god. These rewards come in different forms. Some Champions may be "sent" more followers. Those with a taste for such things might learn potent spells of psychic sorcery, while all Champions will eventually exhibit strange, inhuman powers. Most of the "gifts" offered by the Chaos Gods take the form of physical and genetic changes -- mutations. Some mutations are beneficial, some are harmless -- and others are downright debilitating.

Though such changes can make a Chaos Champion a fearsome warrior, he risks receiving so many such "gifts" and become so mutated, that he loses all control of himself and degenerates into the hideous creature known as a Chaos Spawn. Even the superhuman, genetically-engineered body of an Astartes can only withstand so much genetic corruption and can contain only so much unnatural power. When this limit is finally breached, the Space Marine or other Champion will be lost forever, transformed into a gibbering and mindless Chaos Spawn. Driven insane, Chaos Spawn are nothing more than mindless, howling monsters of tortured, mutated flesh. Most die quickly and painfully, their bodies ripped apart by cascading and uncontrollable mutations as the power of Chaos is made wholly manifest within them. Of those who do not die instantly upon surpassing the limit of the Chaos power that their bodies can withstand, some are abandoned by their warbands to wander the Daemon Worlds until they are slain, while others are kept as pets and war beasts by those who were once their followers.

But the third fate of a Chaos Champion is the reward to which all devotees of Chaos dedicate themselves: ascension to daemonhood. The Champion's ultimate reward is ascension to become a Daemon Prince of his patron god. His flesh is transformed into the immaterial substance of the Warp and his mortal life is entirely cast aside. A follower of Chaos who ascends to become a Daemon Prince is an immortal and all-powerful warrior who will serve his god for all eternity and never know death or fear again. Some Daemon Princes leave their mortal followers behind and join the nightmare hosts of the Daemons of Chaos to plague worlds across the gulfs of space and time as embodiments of the power of their gods. Others choose to remain the leaders of their warband, now granted an eternity to bask in the adoration of their minions and earn perhaps even greater and unimaginable power from the Dark Gods that they have served so well.

Woeful Blasphemies of the Chaos Space Marines
This is a woeful record of recorded blasphemies committed by Chaos Space Marines, compiled from the sealed archives of the Conclave of Kratos, by order of the Herald of the Convocation Senatorum Imperialis, as ratified by Order-in-Camera KKL/706404-4334/X8044. Pursuant to the Declaration of Reunification of the Heresy and Recidivism in each and all of its manifold manifestations with reference to the Sealed Addenda to the 7th Grand Census Armourial:


 * Vengeance from the Void (c.M32) – Across a hundred scattered systems in the western marches of the Segmentum Solar, cult uprisings led by a core of Chaos Space Marine warbands drawn from the Iron Warriors, Night Lords and World Eaters Traitor Legions bring entire planetary governments to their knees in a year of blood and anarchy. With whole sections on the brink of collapse, events take a dramatic turn when a combined force of the Adeptus Astartes emerges from the black depths beyond the spiral arm and launches a sudden and overwhelming attack directly upon the uprising’s command. Though many Space Marines fall in glory, the warlords of the Traitor factions are slain and the uprising fractures into a thousand localized rebellions which are soon put down by local forces. Subsequent Inquisitorial studies claim that these Space Marines are drawn from several Chapters, including the Minotaurs, Carcharodons, Death Eagles and Angels of Absolution. Other evidence however, including their estimated Founding and projected deployment dates, contradict these assertions, consigning the entire event to conjecture.
 * The Hellion War (c.870.M33) – In the wake of the anarchy that followed the murderous internecine conflict of the War of the False Primarch and its aftermath, the Hellion Sector declares its secession from the troubled Imperium. Bloodily attacking its neighbours, it becomes quickly apparent that the sector's rulers had fallen then to the worship of Chaos, and its millions of men-under-arms were corrupted and given over to darkness, while its mass manufactora were turned to churning forth twisted war machines consecrated to the dark gods. The ever widening war swells to ravage more than eighty inhabited systems and uncounted billions die in the fighting. By the dawning of M35, the Hellion Sector and its environs are reduced to little more than a waste zone of barren worlds and dead hive cities.
 * The Sin of Pride (498-601.M34) – Over a dozen campaigns, the Adeptus Astartes Shining Blades Chapter wins a string of victories that ultimately become known as the Beritha Massacres. When the Chapter's methods are questioned they attack their erstwhile allies and the Red Scorpions Chapter appear unheralded to bring them to justice. Much blood is shed in the ensuing war and the Shining Blades Chapter’s true allegiance is revealed as they transform into the servants of the Chaos God Slaanesh. In an act of overweening pride, the Shining Blades declare themselves the "Flawless Host," a sin of hubris for which the Red Scorpions vow to exact punishment.
 * The Dispute of Iron (c.600-730.M34) – Its cause hidden to the eyes of the Imperium, a vast civil war erupts on the Daemon World of Medrengard and rapidly spreads to the other domains of the Iron Warriors. Ancient pacts of fealty and alliance are called upon and scores of Chaos Space Marine warbands, Daemons and Traitor Titan Legions are drawn into the maelstrom of relentless battle. This bitter feud is accredited at creating several sub-factions of Iron Warriors still active to the present day, such as the Steel Brethren, while utterly destroying others such as the Shattered Tower. As abruptly as it was begun the war suddenly ended, leading some to believe that the official conflict had been carried out according to the Daemon-Primarch Perturabo's design in order to weed out the weak and the unworthy from his scions.
 * The Grief of Herodin (973.M35) – A terrible wave of bloodshed and insanity descends from the Nightmare Rifts. Chaos Space Marines, massed cult-hordes and waves of Daemons falling upon the Imperium in an orgy of death later termed not an invasion, but a genocide. Amongst the numberless hosts of the Great Enemy is spotted the Decimator, a towering construct fuelled by the powers of the Warp and bearing the weapons of hybrid xenos manufacture. The war machine is later linked to the heretek Spektraal Cult, thought banished during the Scouring.
 * The Martyred Sons (416.M37) – Inquisitor-Lord Antonius Coil of the Ordo Malleus discovers the current location of the nomadic Hell-Forge of Sarum while conducting an Exterminatus against the warp-tainted Hive Worlds of Goleonda IX, and moves to see it destroyed at last. Along with warships committed from Battlefleet Reductus and several Militarum Tempestus regiments, he mobilized the aid of three Space Marine Chapters, the Brazen Claws, the Sons of the Raven and the Celestial Guard, to strike deep into the perilous Golgotha Wastes against this nightmarish thorn in the Imperium's side. Within sight of the baleful world, the Imperial fleet is ambushed on all sides by the pale warships of the Warp Ghosts and Black Wings Chaos Space Marines and the horrific daemon-engines of their Dark Mechanicus allies of Sarum. In the brutal seventeen hour void battle which follows, the Imperial fleet is encircled and slowly torn to pieces both from without and from within as Daemons rip open passages into realspace deep onboard the stalwart vessels. Only the Chapter fleet of the Brazen Claws breaks free from the trap without crippling losses, while the human contingent of the Imperium's strike forces is annihilated to the last. The ravaged Celestial Guard Chapter will take nearly a century to rebuild from its grievous losses from its stores of gene-seed, swearing bitter vengeance against the Warp Ghosts. The fleet-based Sons of the Raven Chapter, not one of whom escaped the deadly trap, are declared martyred and the great Bell of Lost Souls in the Tower of Heroes on Terra tolls to mourn their passing. Eighteen standard years later, a corrupted Warspite-class Battle-Barge, believed once to have been the Seraphina Carricus of the Sons of the Raven Chapter, is encountered transporting a Warp Ghosts raiding force off Mezoa XV, the withered face of Jo'sun Hernezu the martyred Chapter's last master worn by its revenant captain.
 * Purging of Azoth (999.M37) – At one time known as a firebrand Puritan by whose hand both guilty and innocent had burned on the pyre, Inquisitor Jhovus Theon himself turns renegade when he falls under the influence of the denizens of the Warp and in league with Dark Apostles of the Word Bearers Traitor Legion and triggers a full scale daemonic incursion on the planet Azoth. Theon’s former peers petition the Adeptus Astartes Revilers Chapter for aid, and while victory is theirs, the subsequent Azoth Drop costs the Chapter dearly. Having slain the fallen Inquisitor and purged the cursed planet, the surviving battle-brothers are subjected to mnemonic purgation so that Inquisitor Theon's sins may be expunged for all time from the annals of the Imperium.
 * The Rise of the Impaler (347.M38) – A warband of the World Eaters Traitor Legion descends on the outlying worlds of Paramar, the Storm Lords Chapter mounting a bold defence even in the face of overwhelming odds. The Storm Lords are defeated, a wounded sergeant captured and subjected to brutal cerebral surgery. At length, the sergeant's spirit is broken and he assumes the name and title "Zhufor the Impaler," going on to gain control of the berserker warband known as the Skulltakers. Much later, Zhufor would earn yet another title -- the Butcher of Vraks.
 * The Anshur Summoning (892.M38) – A rebellion led by devotees of the heretical Charnel Cult engulfs the isolated hive world of Anshur, until elements of the Metamarines Chapter of Space Marines are despatched at the request of the Administratum to reclaim Anshur's industrial output for the Imperium. In a meticulously planned campaign of surgical strikes and scorched earth assaults, the Metamarines decimate the cult’s ranks, and in sheer desperation the cult’s leaders invoke the name of dread An'ggrath, summoning forth the Daemon Lord, who annihilates every living thing on the world of Anshur in a seven year long orgy of violence and death.
 * 1st Scouring of Coriolanthe (948.M38) – For three months a warband of the Night Lords Traitor Legion preys upon the gleaming marble cities of Coriolanthe, turning the white-flagged streets crimson with the blood of their victims and decorating the rearing stone towers with looped viscera and severed body parts. At length, the population rises in a maddened frenzy of terror plunging the planet into anarchy. When a Grey Knights Purgation Force, under the mandate of Inquisitor-Lord Baum, arrives to challenge the renegades and restore order, they are confronted not just by the Night Lords, but a force of Traitor Titans. Coriolanthe is reduced to ruins in the ensuing carnage, and the Inquisitor-Lord and all but a handful of Grey Knights are slain.
 * The Cruach Mhorn Massacre (304.M39) – After a twelve year campaign to eradicate rebellious factions within the population of the hive world of Cruach Mhorn, the 3rd Company of the Shadow Hawks is censured for the widespread culling of the population that marks the end of the campaign and leaves the world unable to fulfil production quotas owed to the Administratum. Rather than accept the dishonor of exile on a penitent Crusade, Captain Mahaur leads the survivors of 3rd Company in a series of raids on Imperial fleets and outposts in the Cruach system before vanishing into the lightless void of the Halo Stars.
 * False Flags (799.M39) – An Imperial Navy deep void way station comes under heavy assault by a Space Marine force later identified by their singular heraldry as belonging to the Celebrants Chapter. Objections are lodged at the highest possible levels of the Imperial hierarchy, the Celebrants Chapter Master dismissing the accusations as false and threatening reprisals if they are not retracted. The discord reaches a climax when the Celebrants withdraw from joint anti-pirate operations in the Arataen Deeps, leading ultimately to the loss of three entire sub-sectors. Subsequent Ordo Hereticus investigations determine that the original attack was carried out by the Night Lords in a typically cunning ploy to sow terror amongst the defenders of the Imperium.
 * Relief of Rael's World (814.M39) – With the aid of a cabal of Alpha Legion warleaders, a renegade Dark Angel by the name of Vhalagar conquers the prison planet of Rael's World, installing himself as a pitiless tyrant and subjecting the millions of penal inmates to a bloody regime of inexplicable cruelty. At length, Vhalagar's reign of terror is brought to an abrupt end as a strike force of his former Chapter launches a devastating surgical strike on his strato-keep lair. It is notable that by the time the Dark Angels force their way into the primary penal facility, not a single Alpha Legionary is encountered, leaving Vhalagar to confront his erstwhile brethren alone. Only when he is captured by the Dark Angels and consigned to a transport vessel back to the Chapter fleet is it revealed that his is host to a potent Daemon. Soon after, the vessel is lost to the Warp along with over a dozen brethren of the Dark Angels 1st and 2nd Companies.
 * Garanhir Rebellion (649.M40) – A World Eaters warband, under the command of the notorious murderer Dhalahk, launches a mass incursion against the world of Garanhir, intent upon spilling the blood of the faithful in an unprecedented act of veneration of the Blood God. Expecting to find Garanhir unprepared for attack and ripe for the slaughter, what the Berserkers actually encounter as they charge from the assault ramps of their drop craft is a world already claimed by war, the populace armed and led by the famously militant Inquisitor Malphas Kroh and bolstered by a force of Grey Knights Space Marines. Battle is joined without delay, and while the warriors of Dhalahk make a lethal account of themselves, they are ultimately slain, the entire warband cut down by the defenders.
 * Torment of Sherilax (703.M40) – The population of the pilgrim world of Sherilax falls prey to the fell temptations of the Dark God Slaanesh. Nihilistic pleasure cults on the planet take such sadistic delight in slaughtering the planetary governor’s militia in an intense outbreak of violence, they summon the Bringer of Torments, the Greater Daemon of Slaanesh, Zarakynel.
 * The Death of the Witching Moon (013.M41) – The Forge Moon of Keziah, in the strategically vital Agathon System, falls into an unnatural eclipse which its population is driven to murder and madness in an endless night of horror. The dread forces of the Tenebrae and Company of Misery reign as dark kings amid the nightmare, and the baleful light of the "Witching Moon" that Keziah has become spreads calamity and warp-tainted phenomena wherever it now falls, threatening the entire star system. The first Imperial attacks by the Astra Militarum, squadrons from Battlefleet Ultima and the Inquisition are hurled back in tatters by the madness of the black light and the warp-fuelled savagery of the defenders. It is only by the unexpected arrival of the Charnel Guard Chapter, accompanied by a sacred band of Adepta Sororitas Order of the Black Sepulchre bearing the holy relic known as the Book of Tears before them, that the imminent loss of tens of billions of lives on Agathon Prime is prevented, and the insanity-inducing radiance of the Witching Moon is held back. The Charnel Guard lead a fresh assault as further Adeptus Astartes, including the Iron Hands, Storm Lords and Angels Porphyr, and Adeptus Mechanicus reinforcements arrive, fighting a brutal battle of tank and gunship clashes across the soaring metal canyons which raze the moon's surface and chamber-by-chamber Zone Mortalis actions to purge Keziah of the shadow that has befallen it. The Chaos Astartes inflict fearful losses on their besiegers before they are driven into the deeper darkness of the Warp. In the wake of their retreat, all life is purged from Keziah before it is given back to the hands of the Machine Cult for tech-exorcism and eventual reclamation.
 * The Kynbaex Genocides (709.M41) – Adharon's Reavers, a renegade warband under the former Sons of Guilliman Captain Adharon, instigates a series of bloody uprisings and mutinies across a dozen worlds of the Kynbaex Nebula in an effort to topple the already tenuous and overstretched Imperial presence in the region. Unknown to Adharon, however, the celebrated Rogue Trader Joff Zuckerman and his arch-militant Thor Malkin, later Inquisitor Malkin, are present in the region forging trade routes to outlying systems. Zuckerman responds by ordering an immediate and bloody reprisal, crushing the uprisings with his own fleet and ground forces, led by Thor Malkin, in what became known as the Kynbaex Genocides. Adharon's Reavers are believed to have fled the region rather than face such a massive reprisal and do not appear again in mandated Imperial histories until their involvement in the Siege of Vraks over a century later.
 * Magdelon Incursion (712.M41) – The renegade Bleak Brotherhood makes a compact with a daemonic power for aid in coming wars, the price the entity demands being the casting down of the Crystal City of Magdelon. The renegades enact their pact of the fell bargain, and in so doing attract the attention of the Space Wolves. The ensuing battle amidst the shattered ruins of the Crystal City is so pleasing to the denizens of the Warp that a major daemonic incursion is triggered.
 * Legacy of the Luxor Uprisings (812.M41) – A coalition of Alpha Legion warbands foments an uprising on the Munitorum provender world of Luxor, threatening the supply of war material to war zones across the northern marches of the Ultima Segmentum. The rebellion is put down by the Ultramarines, but the population is so embittered by the Chapter's actions that insurrection and rebellion flares on numerous occasions over the next century. Some strategio-savants even ascribe the fall of the entire Aradme Cluster some eight decades later to chronic under-supply in the aftermath of the 812.M41 uprising.
 * The Skull Harvest (913.M41) – An Administratum tithe-fleet arrives at the three worlds of the Hreidmal Cluster, seeking the tally of lives and produce due the Imperium, only to find each world laid waste. The headless corpses of each world;s inhabitants lie abandoned, not slain in battle but carefully harvested and their skulls piled in great towering obelisks. Attempts to demolish these foul monuments bring the Slaughterkin warband down upon the Imperial forces, led by Warlord Mahaur the Harvester, and soon the skulls of the Administratum factors and regiments assigned to their protection are offered in sacrifice to Khorne atop the rebuilt obelisks.
 * Wars of the Paraxial Succession (917.M41) – When the Adeptus Terra praefect of the Medea Cluster, Lord Sector Parax, is discovered to be harbouring deviant mutation and accused of being in league with the Ruinous Powers, he is executed before a court of his peers without trial. With no successor however, the Adeptus Arbites Lord Marshal takes direct control of the Cluster, his rule so brutal that a dozen uprisings flare up within the year. The entire Cluster erupts into anarchy as the Wars of the Paraxial Succesion draw in Space Marines, both loyal and renegade, from far and wide.
 * Steel Unbound (919.M41) – Following their alliance with Lufgt Huron during the Badab War and their subsequent voluntary internment under license to the Salamanders Chapter, the Executioners are released to begin their century long penitent Crusade. In the first decade of the Crusade, a dozen recidivist cults are purged from the Telamon Cloud and three minor xenos strains infesting the Garya Rifts are exterminated. The most glorious of many action fought during the opening years of the Crusade is against a previously unknown pocket empire deep within the galactic core, entirely in the sway of the Ruinous Powers and maintaining pacts with at least three Traitor Legion warbands and one Traitor Titan Legion. The Executioners earn countless honours far from the glaze of the Imperium, the only witnesses the agents dispatched by the High Lords of Terra to track the penitent Chapter's progress through the lawless void.
 * The Scourging of Kerrack (932.M41) – The Agri-World of Kerrack has long exported the processed root of the cholam trees that cover most of its surface to feed the Astra Militarum regiments prosecuting the Katbargo Crusades. When the primitive harvester clans turn their hand-scythes against their Imperial overseers, the world falls to anarchy and war. Warlord Malfaur the Harvester and his Khorne-worshipping Slaughterkin are found to be behind the Charnel Cults that spring up across Kerrack. The ensuing war is fought on foot beneath the dense canopy and air-to-air in the skies above, large numbers of the native defence militia turning traitor and falling to the worship of the dark gods. Deliverance only comes when the Adeptus Astartes Star Phantoms arrive in system to resupply, and launch an immediate and devastating attack upon the rebel stronghold of Calder's Ark, slaying the Harvester and driving the Slaughterkin from Kerrack.
 * The Constantinus Iconoclasm (981.M41) – The Adeptus Astartes Night Reapers are heavily censured after they abandon the Shrine World of Salvation-Gamma to the massed Chaos Space Marine and mutant forces closing in upon it, turning the guns of their gathered war fleet on the planet in order to grant the population what they consider a merciful end. The Ecclesiarchy lodges such vociferous objections with the Senatorum Imperialis that the Night Reapers are declared to have committed a gross dereliction of duty and, as punishment, are consigned to duty along the outer fringes of the Laanah Rifts. Within a decade, contact with the Chapter is almost entirely lost.
 * The Perun Cross Incident (989.M41) – Having been conclusively linked to the destruction of the fleet of the Rogue Trader Baron Stross Yuen, the Night Reapers Chapter is declared Excommunicate Traitoris. The Minotaurs and Red Templars Chapters are despathed to track them down in the depths of the Laanah Rifts and bring them to the Emperor’s justice. The harrowing of the Night Reapers drags on for three years, with evidence of the renegades harnessing numerous forms of xenos technology amassing throughout. At length, the Night Reapers are cornered onboard a vast, pre-human void construct known as the Perun Cross as they attempt to mine some unknown but no doubt blasphemously potent weapon from its core. In the final assault, a Grey Knights strike force arrives and boards the Perun Cross, but events take a drastic turn as the construct, the entire Grey Knights force and a large number of Minotaurs squads are consumed together in atomic fire. It is assumed that the Night Reapers Chapter is no more, though Imperial forces stationed along the Laanah Rift remain vigilant for signs that any of the fallen brethren survived the Perun Cross incident.
 * The Fall of Forgefane (997.M41) – The Iron Warriors bastion world of Forgefane is overrun by the uncountable warrior organisms of Hive Fleet Leviathan. The Iron Warriors and their million-strong armies of slave-troops mount a masterful but ultimately doomed defence, the scale of which has not been witnessed for many centuries.
 * Ke'lshan Besieged (998.M41) – The Purge warband lays siege to the beleaguered Tan Sept world of Ke'lshan, which is recovering after a series of invasions by both the Imperium and Hive Fleet Gorgon. Their attempt to corrupt the world’s atmosphere, turning it into a corrosive soup that would cleanse the planet of life, are foiled at great cost by Fio'O Sho'Aun, renowned Tau artificer and weaponsmith, whose experimental Remoal throne-fighters duel with airborne Blight Drones for control of the skies of Ke'lshan.
 * The Reapers at Bay (999.M41) – A reclamator fleet of the renegade Night Reapers Chapter, thought destroyed, is cornered by Inquisitor Celaeno of the Ordo Malleus in the bleak expanse of the Caligulan Nebula. With a full company of the Red Hunters Chapter at his command, spearheaded by the ancient Fellblade Tellum Veritatis, Celaeno forces a confrontation on one of the many barren worlds found in the nebula and is met by the warp-tainted armoured vehicles of the Night Reapers. As the Tellum Veritatis duels with the Daemon-touched Typhon Heavy Siege Tank Nidhoggr amid a plain strewn with the broken remains of battle tanks, Celaeno is slammed by an errant shell and the Red Hunters retreat, carving oaths of vengeance into the armoured flanks of Tellum Veritatis.

Chaos Space Marine Traitor Legions
Each of the 9 Astartes Traitor Legions fights using a different style of warfare that is defined by their Legion's culture and nature; also, 4 of the 9 -- the Emperor's Children, the World Eaters, the Thousand Sons and the Death Guard -- are dedicated specifically to the service of 1 of the 4 major Chaos Gods, Slaanesh, Khorne, Tzeentch and Nurgle, respectively. The other 5 Traitor Legions essentially serve the interests of all of the Ruinous Powers collectively in the form of Chaos Undivided.

The 9 Chaos Space Marine Traitor Legions who joined the rebellion of the Warmaster Horus against the Emperor, fully one half of the Space Marine Legions created during the First Founding are (in order of their Founding):

The Emperor's Children
The Emperor’s Children were one of the earliest of the Space Marine Legions to declare itself for Horus and his Traitors, fighting at his side against its own Loyalists during the Istvaan III Atrocity and against the Loyalist Legions during the Drop Site Massacre on Istvaan V. The III Legion and its Primarch Fulgrim had been corrupted following its encounter with the Slaanesh-worshipping xenos race known as the Laer and their world of Laeran late in the Great Crusade. The rot spread quickly through the Legion, and the Emperor’s Children embraced Chaos, particularly the Prince of Pleasure, in all its depravity. Little trace can now be seen of the original armour and equipment of the Emperor’s Children, covered as it is by skins of iridescent fur or scales, jewels, or the fantastical renderings of screaming faces or rutting beasts. The Emperor’s Children fight for sensation and sensory overload, bringing a clashing cacophony of sound, colour, and energy to the battlefield.

The Iron Warriors
The Iron Warriors once formed the Emperor’s legion of siege troops. They fought on a hundred worlds in the Great Crusade, laying siege to alien citadels and the palaces of Heretics with equal gusto. The Iron Warrior’s Primarch, Perturabo, excelled in the arts of siege and trench warfare above all else, and his treatise on fortifications and their reduction formed the basis of several sections of the Tactica Imperialis. The Iron Warriors betrayed the Emperor on Istvaan V, their mazes of bunkers and razor wire becoming a death trap for their Loyalist brethren instead of the sanctuary they promised to be. The Iron Warriors wear relatively unadorned armour that is commonly pieced together from the older marks for its heavier frontal protection. They favour heavy weaponry like Lascannons or Missile Launchers for long-range engagements, although well-equipped Iron Warriors Assault Squads are also rightly feared.

The Night Lords
Led by their saturnine Primarch, Konrad Curze (also known the Night Haunter) the Night Lords were greatly feared even before the Heresy. Curze believed in the use of terror as a weapon and his foes quickly learned to fear the night. The Night Lords were one of the first Legions to join Horus’ rebellion, turning on what they saw as a weak-willed Emperor incapable of having the strength to lead. Even after Horus’ defeat the Night Lords have continued to wage an unremitting campaign of terror against the Imperium. The Night Lords refuse to follow any of the Chaos Gods, and have become cynical, hard-bitten, and frighteningly ruthless warriors. They fight for the pleasure of it, and for the material rewards it can bring, and not for the worship of some deity. They look down upon their more dedicated brethren, whether they are fanatical Chaos Space Marines like the World Eaters, or zealous Loyalist Space Marines like the Dark Angels.

The World Eaters
Under the Primarch Angron, the World Eaters underwent psycho-surgery that transformed an already fierce legion into bloodthirsty berserkers through the use of cortical implants known as the Butcher's Nails pioneered on their Primarch's homeworld of Nuceria. When they betrayed the Imperium, it was of little surprise that the vast majority dedicated themselves to Khorne. The XII Legion fractured after the Heresy, scattering into warbands across the galaxy. However, any member of the World Eaters is likely to be bloodthirsty and violent. As is fitting to their patron God, the World Eaters wear armour as red as arterial blood, edged with brass and decorated with skulls and symbols of Khorne. Most disdain long-ranged warfare, preferring to close with the enemy to kill them with Chainaxe, Power Sword, and (if need be) Bolt Pistols.

The Death Guard
The Death Guard followed Horus into heresy, their sense of loyalty to their Warmaster and their Primarch, Mortarion, triumphing over their duty to the Emperor on distant Terra. The rebel Death Guard Legion was marooned in the Warp during the long journey to Terra to join the attack on the Imperial Palace. A mysterious, unstoppable contagion spread through the trapped fleet, putrefying all it touched. Mortarion himself became infected and in his delirium he called upon the Powers of Chaos to aid his Space Marines. Mortarion’s fevered ravings were answered by Nurgle, and Mortarion became Nurgle’s foremost mortal Chaos Champion and eventually his Daemon Prince. The Death Guard survived but they continue to bear the marks of Nurgle’s first blessings upon them. Their once-white armour became stained and cracked where the bubbling foulness of their mortal bodies has erupted to the surface. They bear the three-lobed mark of Nurgle rendered as flies or rotting heads upon banners and shoulder guards. Their Bolters and Chainswords are caked with filth and rust but are no less deadly. Plague and contagion have become the Death Guard’s primary weapons and they can be found anywhere in the galaxy spreading Nurgle’s foul blessings.

The Thousand Sons
The path to damnation for the Thousand Sons Legion of Space Marines was longer than most, but its final plunge more complete than any. Even before the Horus Heresy the Sons’ cyclopean Primarch Magnus the Red led his sons in the study of arcane lore and the practice of sorcery despite the Emperor’s disapproval and the outright ban on such practices at the Council of Nikaea. When Horus gathered his forces the Thousand Sons tried to use their occult powers to warn the Emperor of the Warmaster's betrayal. Disastrously the Emperor was mistrustful of anything tinged by Chaos such as the use of psychic sorcery that He had expressly forbidden at Nikaea and He declared the Thousand Sons' Primarch to be taken captive and brought back to Terra for his disobedience. Leman Russ and the Space Wolves Legion were sent to devastate the Thousand Sons’ homeworld of Prospero. To survive and protect their accumulated wisdom, the Thousand Sons sought the patronage of the Chaos Power Tzeentch, Changer of the Ways, greatest master of magic among the Chaos Gods. During the terrible battle known as the Burning of Prospero, Tzeentch transported Magnus and his surviving sons to the Daemon World in the Eye of Terror called the Planet of the Sorcerers. The surviving Thousand Sons have been split by internal schisms, their pursuit of occult knowledge estranging them to each other and even their cyclopean Primarch. A cabal of renegade Sorcerers led by their once-Chief Librarian Ahriman unleashed a great magic upon the Legion to prevent further mutation and corruption of its members by Chaos. This Rubric of Ahriman reduced most of the Thousand Sons to soulless suits of animated armour known as Rubric Marines, but left the surviving Sorcerers unmatched in power.

The Black Legion
The Black Legion is the only Traitor Legion to have changed its name in its ten thousand years of exile. In the First Founding the XVI Legion was created as the Luna Wolves. The Emperor subsequently allowed his favoured son Horus to rename the Legion “the Sons of Horus” in recognition of its accomplishments in the Ullanor Crusade and in honour of its Primarch. The Sons of Horus willingly followed their beloved Primarch and Warmaster into rebellion, fighting at the very forefront of his most important campaigns. When Horus was defeated by the Emperor at the Battle of Terra, the Legion’s morale was shattered; their patron, their father, was gone. After the battle for the Imperial Palace the Sons of Horus renamed themselves the Black Legion, changing their Legion colours to black in memory and mourning of their fallen Primarch. They gave themselves to the worship of one Chaos Power after another and lost many of their number through possession and madness. The hardened survivors lead warbands against the Imperium to this day, still eager to expunge the bitter memory of Horus’ defeat. The Black Legion has been reforged under the strong leadership of Abaddon the Despoiler, the former First Captain of the Sons of Horus, who has claimed Horus' mantle as the Warmaster of Chaos Undivided.

The Word Bearers
Lorgar, Primarch of the Word Bearers Legion, was a scrupulous and dedicated follower of the Imperial Cult, and in many ways was the founder of the religion of Emperor-worship called the Lectitio Divinitatus that would one day become the Adeptus Ministorum. He led his XVII Legion in the building of vast monuments and immense rituals during the Great Crusade to secure the faith of those that were conquered in the God-Emperor. The Emperor rejected Lorgar’s efforts however, telling him that he needed his Space Marines to fight, not worship and serve the secular Imperial Truth which disdained all religion and superstition. Lorgar’s disillusionment with the Emperor’s impiety drove him to worship of the Chaos Powers during the Pilgrimage of Lorgar undertaken some 43 standard years before the start of the Horus Heresy, entities that truly demanded worship and sacrifice from their followers. When Horus raised his banner the Word Bearers, who had largely driven Horus into corruption by Chaos from behind the scenes, eagerly followed him into rebellion along with a thousand hidden Chaos Cults they had established on the worlds they had brought into Imperial Compliance in the last days of the Great Crusade. The Word Bearers' fanatical zealotry has become dedicated to the worship of Chaos in its purest form, unadulterated by the veneration of any particular Chaos Power over the others. They are the only Traitor Legion that still maintains the rank of Chaplain, the darkly twisted individuals holding this office now known as Dark Apostles and leading their brethren in heretical prayers and insane catechisms. Immense cathedrals and rune-etched monuments still rise in the wake of the Word Bearer’s conquests, but now they are blasphemous dedications to the glory that is Chaos.

The Alpha Legion
The Alpha Legion was the twentieth and final Legion created in the First Founding. During the Great Crusade the XX Legion earned renown for its strict discipline and organization. The Alpha Legion strove hard to outshine its brethren in all things and prove their worthiness to be among the older Legions. The war-lust of the Alpha Legion easily led them into heresy when Horus declared himself against the Emperor, though some legends say that the Alpha Legion secretly remains loyal to the Emperor in perhaps the greatest of the many deceptions and ploys it has worked. Here at last was their chance to prove themselves against opponents just as tough, as battle hardened, and ferocious as themselves. The Alpha Legion did much to ravage the Eastern Fringe during the Heresy, pursuing their own set of objectives far from Terra. In the ten millennia since they have continued to strike from bases hidden all over the galaxy. Unusually the Alpha Legion actively cultivates Chaos Cultists and rebels, multiplying their impact many times over. The Inquisition holds a special loathing for the Alpha Legion for their part in spreading Chaos Cults and fanning the embers of heresy into the raging fires of outright rebellion.

Renegade Space Marine Chapters
Through the passing of the centuries since the Horus Heresy, the Forces of Chaos have been further swelled by those Space Marines from the later Foundings who have turned from service to the Emperor of Mankind to pursue their own agendas. According to the current records of the Inquisition's Ordo Malleus, approximately 50 Loyalist Chapters or elements of Loyalist Chapters have turned Renegade in the ten millennia since the Horus Heresy. Examples include the Sons of Malice, the Damned Company of Lord Caustos, the Violators, the Thunder Barons, and the Astral Claws (known as the Red Corsairs since their rebellion against the Imperium during the Badab War). A more complete list can be found here.

Freed from the Imperial dogma and traditions of their Chapter, these so-called Renegade Space Marines fully indulge the needs of their superhuman bodies and their militant minds. They most often become corsairs, pirates and mercenaries, using their unparalleled combat skills to garner wealth and power for themselves, rising as tyrannical masters of pirate fleets and the masters of desolate frontier worlds. As they explore their new freedom from the discipline and strict purpose of the Adeptus Astartes, these Space Marines inevitably turn at some point to the Chaos Gods to gain more power to do as they will. From this point on, they are fated to walk the path of the Chaos Champion as much as any of the original Traitors of the Horus Heresy. These Renegades are hunted men -- loathed by all the other Space Marine Chapters, who consider it their foremost duty before the Emperor to destroy any Renegade Astartes lest their vile shame and dishonour leave a black stain upon all the Loyalist Space Marines who have never turned their face from the light of the Emperor or their duty to Mankind for their own selfish gain.

Though never equal in size or power to the original Astartes Legions, a modern Space Marine Chapter is a potent military force in its own right and when an entire Chapter turns Renegade it presents a grave threat to the Imperium. With all the resources of a Space Marine Chapter at their disposal, the Renegades of Chaos destroy Imperial armies, conquer Imperial worlds and despoil whole sectors of the Imperium. Such events warrant an extreme response from the Imperial forces, not to mention the other, Loyalist Space Marine Chapters. It is perhaps the greatest test of faith for a Space Marine to fight another Astartes and these internecine conflicts often have a terrible effect on other nearby Chapters. In these circumstances, such inter-Chapter wars tend to escalate quickly, engulfing many worlds with bloodshed. On Occasion, those forces sent to deal with the Renegade Chapter may actually end up, in whole or in part, becoming corrupted and joining with those they were sent to destroy, just as happened to many among the Traitor Legions so long ago.

An example of just such an outcome infamously took place in the 34th Millennium during the Obscuran Uprisings. During the course of 400 Terran years of anarchic separatist rebellions that shook much of the Segmentum Obscurus, at least 7 Loyalist Space Marine Chapters broke their oaths to the Emperor and took part in the looting and pillaging of hundreds of these Imperial worlds. Of these Chapters, 2 of them, the Sons of Vengeance and the Silver Guards -- had at first fought on the side of the Imperium but turned Renegade after their actions against the Chaotic Free Council of Hannedra II.

The Forces of Chaos
The Forces of Chaos is an all-encompassing term that includes the Chaos Space Marines and all the other beings and entities who serve the Ruinous Powers of Chaos and make war upon the Imperium of Man and the many other intelligent races of the Milky Way Galaxy. Among their number are included the Traitor Legions and Renegade Space Marines, human, mutant and alien Chaos Cultists, Traitor Imperial Guard, Traitor Titan Legions, the Tech-priests of the Dark Mechanicus, Chaos Spawn cannon fodder, and daemons of every shape and level of power as well as countless other foul beings too horrific to be mentioned here. All of these forces can be led into battle by the Chaos Space Marines, who are collectively the most powerful mortal servants of the Ruinous Powers who have ever lived.

The Lost and the Damned
There are also many normal humans and mutants who serve the Ruinous Powers as Chaos Cultists or belong to ancient regiments of the Imperial Army, the Traitor Titan Legions or the Dark Mechanicus. These groups joined Horus in his rebellion and then fled with the Traitor Legions into the Eye of Terror 10 millennia ago after Horus' defeat. These groups are often used by the Chaos Space Marines to bolster their ranks. These Traitors, mutants and heretics are collectively labelled the "Lost and the Damned" by the Inquisition.