With the warp storms at last receding, the Emperor of Mankind launched The Great Crusade, a triumphant campaign to reunite the sundered worlds of humanity and reclaim the stars for a reborn Imperium. From Terra His fleets surged outward, bearing the promise of unity, reason, and an end to the long ages of isolation.
At the vanguard marched the Space Marines, superhuman warriors organised into the Legiones Astartes and led by the Emperor's own gene-sons, the Primarchs, scattered at birth across the galaxy and reclaimed one by one. Beside them fought the golden Adeptus Custodes, the Emperor's personal guardians, and the countless soldiers and war machines of a species remembering its own might.
World after world was brought into Compliance, its people enlightened and its false gods cast down, for the Emperor preached the Imperial Truth: that there were no gods, that the warp held no divinity, only peril to be mastered by reason. Where diplomacy failed, the Legions delivered fire and annihilation to any who would not join or submit.
For two centuries the Crusade carried human dominion across a million worlds, a feat unmatched in all history. Yet its very grandeur sowed the seeds of catastrophe, for the Emperor's silence regarding the true nature of the warp left His finest sons vulnerable to the whispers of powers He refused to name.