A Black Crusade is a colossal invasion launched from the Eye of Terror, in which the scattered warbands of Chaos unite beneath a single warlord to hurl themselves against the Imperium. These are not mere raids but galaxy-shaking campaigns of conquest and desecration, the greatest expressions of the Long War waged by the Chaos Space Marines and their daemonic allies.
Most Black Crusades in recorded history have been led by Abaddon the Despoiler, heir to Horus and Warmaster of Chaos Undivided. Through terror, ambition and dark pacts, he binds rival Traitor Legions, renegade fleets and daemon hosts into a single monstrous host, unleashing them upon the Imperium's borders with catastrophic effect.
Each Black Crusade leaves worlds burning and defensive lines shattered in its wake. Whole sectors have been plunged into darkness, star fortresses toppled and populations enslaved or slaughtered. To the Imperium they are apocalyptic events, harbingers that the Dark Gods have once more turned their gaze upon the realms of Mankind.