Chaos Space Marines - Renegade Space Marine Chapters: The Traitor Legions are not the only Space Marines to fall to Chaos. Through the passing of the Terran 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.With each new millennium, dozens of disillusioned or power-hungry Chapters defect, just as Horus did. Only the High Lords of Terra and the Inquisition have any idea of how deep the rot goes. Nonetheless, some Renegades have achieved such notoriety that their legends resonate throughout entire sectors.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.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, or for protection, since prolonged independence will jeopardize them if the bloodthirsty Traitor Legions were to become aware of their existence.From this point on, they are fated to walk the path of the Chaos Champion. 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.This is rare however, as most Chapters usually operate within a number of theatres simultaneously. Therefore, it is usually separate companies or detachments that will turn Renegade, and will abandon or turn on their Loyalist brethren. 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. Other Chapters are then employed to suppress the rebellion, but 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 occurred to many amongst 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 Chaos-corrupted Free Council of Hannedra II.