Based on data from a story, 10,000 years ago, Warmaster Horus, Primarch of a Luna Wolves (afterwards Sons of Horus, & the Black Legion) was tainted by Chaos while he recovered from wounds on the planet Davin, getting been inducted into the "warrior lodge" that was little to the higher degree a Chaos cult. Horus introduced a "warrior lodge" idealistic to 5 of the Chapters under his comm&, and spread to half of the twenty Legions. A corrupted ones wholeheartedly followed Horus's idethe of a recently Imperium of Man, with Horus as Emperor.

Unaware of the treachery, a Emperor sent Horus to Istvaan III, in which the Regal governor had declared a patterns independent of the Empire, to suppress the rebellion. Horus utilized the bioweapon that killed the people of 12 billion around seconds; releasing a psychic shockwave said to have been loudly than a Astronomicon.

A Emperor ordered a Inquisition to purge a Adeptus Astartes of a Chaos contamination, & so began the Horus Heresy. Nine Legions of Space Marines betrayed the Empire for Horus, world health organization experienced destroyed ternary others. A Emperor, Primarch Sanguinius of the Blood Angels, and Primarch Rogal Dorn of the Imperial Fists attacked Horus on his ship. Horus slew Sanguinius whenever he refused to betray a Emperor, & a Emperor slew Horus within battle. Mortally hurt, a Emperor ordered his fleet to cause a Traitor Legions into a Eye of Terror, a rift within space in which reality & the Warp merge.

A Traitor Legions & their Primarchs come: Sons of Horus - Warmaster Horus Thousand Sons - Magnus the Red World Eaters - Angron Night Lords - Konrad Kurze (Night Haunter) Word Bearers - Lorgar Alpha Legion - Alpharius Iron Warriors - Perturabo Death Guard - Mortarion Emperor's Children - Fulgrim

A todays leader of the Chaos Marines is Abaddon the Despoiler, the "son" of Warmaster Horus, world health organization has led Long dozen Black Crusades against a Imperium of Human.

There are too numbers of man world health organization help Chaos - traitors, mutants & heretics. These scum of A universe come jointly labelled The Lost and the Damned.