A Black Crusade is when the Forces of Chaos manage to unite under the leadership of a powerful Champion of Chaos and launch a massive attack from their base within the great Warp rift called the Eye of Terror against the worlds of the Imperium of Man. The most devastating Black Crusades were led by the Warmaster of the Black Legion, Abaddon the Despoiler, the self-proclaimed heir of Horus, who has led 13 Black Crusades against the Imperium, the most recent of which was the 13th Black Crusade in 999.M41.
The 1st Black Crusade occurred in the middle of the 31st Millennium, not long after the end of the Horus Heresy in 731.M31. Utilizing the region of calm around the Eye of Terror known as the Cadian Gate, Abaddon led the combined forces of the Traitor Legions against scores of Imperial worlds, and was responsible for millions of deaths in the first week alone. Multiple worlds were lost before the Imperium could fight back effectively, and although the Black Crusade was defeated, the Imperium was forced to heavily fortify the surrounding Cadian Sector.
Over the course of the intervening ten thousand standard years, Abaddon has launched a further twelve Black Crusades. Millions of other attacks have been made on the worlds of the Cadian Gate by Daemon Princes and lesser Chaos warlords, but the title of Black Crusade is reserved for the times when Abaddon seems to be able to unite all of the Forces of Chaos in the pursuit of one goal--the destruction of the Imperium of Man, the greatest bastion of Order in the galaxy.
The 41st Millennium saw two Black Crusades. The 12th Black Crusade, also known as the Gothic War, was Abaddon's attempt to capture the ancient Eldar artifacts known as the Talismans of Vaul, but known to the Imperium as the six Blackstone Fortresses. The Eldar allied themselves with the Imperium to defeat the Chaos forces, and were successful, although Abaddon escaped with at least two of the Blackstone Fortresses.
The Thirteenth Black Crusade began during the 999th year of the 41st Millennium, and resulted in the largest mobilisation of both Imperial and Chaotic forces seen since the Horus Heresy. In this campaign, at least one of the Blackstone Fortresses was destroyed by Necron raiders; the fortresses, also known as the Talismans of Vaul by the Eldar, were originally designed to defeat the "Star Gods" - the C'tan, during the ancient War in Heaven millions of years ago between the C'tan's Necron servants and the Old Ones.
The Thirteenth Black Crusade was the background to Games Workshop's world-wide Eye of Terror Campaign, which resulted in a minor victory for the Forces of Chaos and gave Abaddon his long-sought a foothold on the Cadian Gate, though he suffered devastating losses to his fleet to secure it. Admiral Quarren led an Imperial counter-attack that drove off Abaddon's Chaos-corrupted Blackstone Fortress which had been possessed by an avatar of the Chaos God Slaanesh, but Abaddon's foothold in the Gate remains intact, with fighting still ongoing on Cadia and the surrounding worlds as the 42nd Millennium dawns. In response, the Imperium has stripped the garrisons along its far Eastern Fringe to reinforce the Cadian Gate, which resulted in a full retreat of the Forces of Chaos from the Cadian Gate, resulting in the current stalemate. However, this weakening of Imperial defences hastened the onslaught of the Tyranid Hive Fleet Leviathan and the latest expansion of the Tau Empire until it was brought to a halt in the Zeist Campaign.
List of Black Crusades
- 1st Black Crusade (circa 781.M31) - Abaddon the Despoiler, the new Warmaster of Chaos Undivided, makes his first attempt to launch a new offensive against the Imperium of Man folowing the Horus Heresy and initiates the First Battle of Cadia.
- 2nd Black Crusade (597.M32) - The 2nd Black Crusade saw another failed assault by the Forces of Chaos from the Eye of Terror upon the defences of Cadia.
- 3rd Black Crusade (909.M32) - The 3rd Black Crusade was carried out by the great Chaotic force known as the The Host of Tallomine. The Host was lead by the Daemon Prince Tallomin but the assault was crushed by Imperial forces lead by the Space Wolves Space Marines.
- 4th Black Crusade (circa 001.M34) - Abaddon's forces succeed at carrying out the destruction of the Citadel of Kromarch on the world of El'Phanor before the Forces of Chaos are crushed once more by the Imperium's stalwart defenders.
- 5th Black Crusade (723.M36) - Doombreed, an ancient Daemon Prince of Khorne whose existence precedes that of the Imperium itself, declares war on the Adeptus Astartes. The Warhawks and the Venerators Chapters of Space Marines are lost in the fighting.
- 6th Black Crusade (901.M36) - No information about this conflict is currently known in Imperial records.
- 7th Black Crusade (811.M37) - The 7th Black Crusade is also known in Imperial records as the Ghost War. It is during this conflict that the Forces of Chaos slaughter a large portion of the Blood Angels Chapter of Space Marines at the Battle of Mackan.
- 8th Black Crusade (999.M37) - No information about this conflict is currently known in Imperial records.
- 9th Black Crusade (537.M38) - No information about this conflict is currently known in Imperial records.
- 10th Black Crusade (001.M39) - This Black Crusade is also known as the Conflict of Helica, during which the Iron Warriors Chaos Space Marines fought the Iron Hands on Medusa.
- 11th Black Crusade (301.M39) - No information about this conflict is currently known in Imperial records.
- 12th Black Crusade (139.M41) - Better known as the Gothic War, this Black Crusade was fought for control of the Gothic Sector in the Segmentum Obscurus between the Chaos forces of Abaddon the Despoiler and the defenders of the Imperium.
- 13th Black Crusade (999.M41) - The greatest of the Champions of Chaos, Abaddon the Despoiler, launches an all-out attack of the forces of Chaos Undivided on Cadia. The Forces of Chaos succeed in gaining a foothold on the surface of Cadia, but become trapped there when their fleet is driven back into the Eye of Terror by the Imperial Navy. A bloody stalemate ensues within the Cadian Gate.
- Codex: Chaos Space Marines (3rd Edition)
- Liber Chaotica: Khorne
- Codex: Eye of Terror (3rd Edition)
- Battlefleet Gothic: "The Galaxy"