The Heretic Astartes, often known as Chaos Space Marines or Traitor Marines, are Astartes that have turned their backs on the Imperium of Man. Having cast aside their duty to protect mankind, they now dedicate themselves to their own perverse pursuit of power and the glory of the Ruinious Powers.
Many Heretic Astartes are members of the original nine Traitor Legions that betrayed the Emperor at the dawn of the Imperium during civil war known as the Horus Heresy. However, inevitably, over the following ten millenia, many other Space Marines have joined their number. Combining the super human abilities of an Astartes with the gifts of the Chaos Gods, the Heretic Astartes are some of the most dangerous enemies mankind face.
- Transhuman Physiology: Like all Space Marines, Heretic Astartes are imbued with physical capabilities far beyond that of normal humans, making them capable of immense feats of physical strength and endurance.
- Veterans of the Long War: For ten thousand years, the Heretic Astartes of the Traitor Legions have waged war against the Imperium of Man. Their hatred burns as brightly as it did during the Horus Heresy, driving them on with a dark purpose.
- Faithful of the Dark Gods: Having turned their back on Emperor and their duty to mankind, the Heretic Astartes pledge their souls to the Chaos Gods. Many worship them as a whole pantheon, such as the Word Bearers, while others dedicate themselves to one individual god. Others, such as the Night Lords, see the powers of Chaos as mere tools to be used in their depraved campaigns of bloodshed.
- The Horus Heresy. 005.M31 — 014.M31
- Horus Lupercal, Warmaster of the Imperium, turns his back on the Emperor alongside eight of his brother Primarchs and their legions to become the first Chaos Space Marines.
- The galaxy is engulfed in a cataclysmic civil war that nearly brings the Imperium to its knees.
- Despite the Imperium’s pyrrhic victory and Horus’s death at the Battle of Terra, the surviving Heretic Astartes are able to flee across the galaxy to the Eye of Terror – beginning the Long War.
- The Badab War. 901-912.M41
- Four full Space Marine chapters renounce their views to the Imperium. After a protracted and bloody civil war, the survivors flee into the Warp Storm known as the Maelstrom where they become the Red Corsairs – the largest non-Traitor Legion Heretic Astartes force in the galaxy.
- The First War of Armageddon. 444.M41
- Angron, Daemon Prince of Khorne and Primarch of the World Eaters legion, leads a vast assault on the Imperial world of Armageddon. The arrival of the entire Space Wolves chapter, as well as a strike force of over 100 Grey Knights, manages to stem the tide of daemons, cultists and Chaos Space Marines and banish Angron back to the Warp.
- The Thirteenth Black Crusade. 999.M41
- Abaddon the Despoiler, Warmaster of Chaos and the Black Legion, unleashes a massive force of Traitor Marines, mutants, heretics and daemons upon the fortress world of Cadia and its surrounding systems. It is the largest conflict between Chaos and the Imperium since the Horus Heresy. His victory opens the Great Rift – a massive, galaxy-spanning Warp Storm that tears the Imperium in two.