A Black Crusade is when the forces of Chaos manage to unite under a particularly strong leader and go forth en masse to wage war against the Imperium of Man. There have been thirteen Black Crusades to date, all started by Abaddon the Despoiler, Warmaster of the Black Legion and the (rumoured) clone-son of Horus.
Prior to the 13th Black Crusade, each of Abaddon's 12 assaults had failed. The 13th Black Crusade was the background to the world-wide Warhammer 40,000 Eye of Terror campaign, which resulted in a minor victory for the forces of Chaos. Now having gained a foothold on the Cadian system, he is able to strike out and attack from real space, as opposed to traversing the Immaterium.
List of crusades
- Failed attack on defences of Cadia. (Liber Chaotica: Khorne)
- The Host of Tallomine. Daemon Prince Tallomin leads attack that is crushed by the Space Wolves. (Liber Chaotica: Khorne)
- Destruction of the Citadel of Kromarch on El'Phanor before crushed. (Liber Chaotica: Khorne)
- Doombreed, a prince of Khorne declares war on the Adeptus Astartes. The Warhawks and the Venerators are lost. (Liber Chaotica: Khorne)
- Launched during the Age of Strife. (Liber Chaotica: Khorne)
- The Ghost War. (Liber Chaotica: Khorne)
- The Conflict of Helica. Iron Warriors fight Iron Hands at Medusa. (Liber Chaotica: Khorne)
- The Gothic War. (Liber Chaotica: Khorne)
- Attack on Cadia. (Codex: Eye of Terror)