The Great Crusade
Ten thousand years of conquest, crowned by the galaxy's greatest betrayal.
The Great Crusade is the foundational military campaign of the Imperium of Man, a roughly ten-thousand-year reconquest of the scattered human worlds of the galaxy, launched by the Emperor of Mankind after he unified humanity on Terra. Guided by his twenty gene-seed sons—the Primarchs—and their vast Space Marine Legions, the Crusade sought to reclaim lost colonies, purge xenos threats, and forge a single human empire stretching from segmentum to segmentum. In the context of Darktide, the Great Crusade is the deep historical bedrock beneath every mission the player undertakes. The hive-cities of Tython, the rigid Inquisitorial structures, the ever-present fear of Chaos corruption, and the very existence of the Ordo Malleus all trace their origins back to the triumphs and catastrophic failures of that era. Without the Crusade, there would be no Imperium to defend, no Heresy to remember, and no reason for the Inquisition to hunt corruption in the underhive.
Quick Facts
- Leader
- The Emperor of Mankind
- Commanders
- The twenty Primarchs and their Space Marine Legions
- Primary objective
- Reconquer lost human worlds and unite them under a single Imperium
- Ending event
- The Horus Heresy (civil war among the Legions)
- Lasting legacy
- The Imperium of Man
- the Space Marine Chapters
- and the Inquisition's mandate
Lore & Background
After unifying the warring human factions on Terra, the Emperor turned his gaze outward. Humanity had once spread across the galaxy, but the fall of the Old Ones and the long Dark Age of Technology had scattered the race into isolated, vulnerable colonies. The Great Crusade was the Emperor's answer: a relentless, galaxy-spanning campaign to find every human world, reclaim it, and bind it into a single political and military entity. The twenty Primarchs—each a superhuman warlord raised from the Emperor's own genetic material—led the twenty Space Marine Legions in a wave of conquest that reshaped the galaxy's demographics and power structures over millennia. The Crusade was not merely a military operation. It was a civilizing project. The Emperor's agents established the administrative frameworks, the tech-priestate's dominance over machine worship, and the rigid hierarchies that would define Imperial life for ten thousand years. Worlds were conquered, subjugated, and integrated. Xenos civilizations were identified and, in most cases, designated as existential threats to be destroyed. The philosophical and political seeds of the Imperium's later rigidity, its xenophobia, and its absolute devotion to the God-Emperor were all sown in this era. The Crusade's end was not a victory but a wound that never healed. The Horus Heresy—the betrayal of the Warmaster Horus and his allies, who turned to the Ruinous Powers of Chaos—unleashed a civil war that shattered the Legions, killed or corrupted several Primarchs, and ultimately drove the Emperor into the Golden Throne, where he has languished for ten thousand years. The Great Crusade's legacy is therefore double-edged: it created the Imperium, but it also created the Inquisition, the fear of Chaos, and the institutional paranoia that defines the world the player navigates in Darktide.
Reader's Guide
The Great Crusade is the 40K equivalent of a founding myth: the Emperor unified humanity on Terra, then launched a ten-thousand-year campaign to reclaim every lost human world and build the Imperium. The twenty Primarchs, his superhuman sons, led the Space Marine Legions in this conquest. The campaign ended in civil war—the Horus Heresy—when half the Legions turned to Chaos, and the Emperor was left entombed on the Golden Throne. In Darktide, you live in the long shadow of that story. Tython, your hive world, was almost certainly conquered and integrated during the Crusade. The rigid caste system, the Magistrate's authority, the Tech-Priests' monopoly on machinery, and the Inquisition's omnipresent suspicion all trace back to the institutional structures built in that era. The Ordo Malleus, your employer, exists specifically because the Heresy proved that Chaos corruption can infect even the Emperor's own champions. Every mission you take—hunting a Chaos cult in a factory, tracking a xenos agent, containing a psyker's outbreak—is a small echo of the galaxy-wide war that the Crusade started and the Heresy made permanent. When in-game codex entries reference the "old wars" or the "time before the Throne," they are pointing at the Great Crusade. The Imperium you serve is not a natural order; it is a scar, a wound that was never allowed to close, and the Inquisition is the bandage that keeps it from reopening.
More in Lore & 40K Context
Elsewhere in Warhammer 40000 Darktide
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