Chaos Space Marines - 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 XVIth 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. The Warmaster then 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 flagship, the Vengeful Spirit, during the Battle of Terra that saw the conclusion of the Horus Heresy, the remnants of the nine 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, two other Traitor primarchs were killed during or shortly after the Heresy (Alpharius of the Alpha Legion and Konrad Curze of the Night Lords).The six surviving Traitor primarchs have since been transformed into Daemon Princes by the Chaos Gods. These Daemon Primarchs rarely took part in the affairs of their Legions before the birth of the Great Rift. 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 organisations and instead devolved into a series of separate and often competing smaller units called "warbands." The Traitor Marines who command these warbands, all potent Chaos Champions, seek 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 ten millennia.The closest thing to unity that has appeared amongst the Traitor Legions and other Chaos Space Marines is when Abaddon the Despoiler, the Warmaster of Chaos and leader of the Black Legion, launches one of his periodic Black Crusades into Imperial space under the banner of Chaos Undivided. These were temporary periods of unity amongst all the forces of Chaos when they seek to overwhelm the Imperium's defences 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 nine Traitor Legions, and he has led twelve 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 proved the most successful for the forces of Chaos since the Horus Heresy. The Chaos troops managed to destroy the Fortress World of Cadia, at last cracking open the Cadian Gate. Shortly afterwards, the Great Rift was born, as the strains wrought upon reality by the 13th Black Crusade caused realspace to crack along a line running from the Eye of Terror in the galactic west to the Hadex Anomaly in the east. The forces of Chaos are now on the march as never before, though the defenders of the Imperium have also found themselves reinvigorated by the resurrection of the Primarch Roboute Guilliman.Yet the Emperor's servants find themselves pressed as never before from all sides by Chaos and other xenos factions. Abaddon believes it will not be much longer before the Black Legion and the other servants of the Ruinous Powers will once more stand upon the soil of Terra. Then the galaxy will tremble as the servants of the Dark Gods rip the Corpse Emperor from His Golden Throne and claim the souls of Mankind for their own.