The greatest betrayal in human history began with a single wound.
Horus Lupercal. First found of the primarchs, most brilliant of the Emperor’s sons, named Warmaster at Ullanor and given command of the entire Great Crusade. If you had stood where I stood, in those years, you would have loved him too. Everyone did. That was the tragedy of it.
The Wound on Davin
On the moon of Davin he took a hurt that should not have been able to kill him — and was dying of it. His sons, desperate, listened to the Word Bearer Erebus, and carried their father’s body to the Delphos, the serpent temple on Davin. What happened within was no healing. It was a ritual of the warp. Unmoored from his flesh, shown lies by a creature wearing the face of his dead friend Sejanus, Horus was offered a choice — and he chose. Understand that, before you weep for him: the Warmaster was deceived, but in the end he chose.
Isstvan III: the Culling of the Loyalists
What followed came fast and terrible. At Isstvan III he gathered every warrior in his legions — and in three others — whose loyalty to the Emperor outweighed their loyalty to him, sent them down to the surface as one force, and culled them in a single blow. Billions died in the bombardment. His own sons, burning below him.
Isstvan V: the Dropsite Massacre
At Isstvan V, worse. Seven legions came to bring him to justice. Four of them were already his. When the trap closed on the black sand of the dropsite, three loyal Legions were all but destroyed in a single day. The Imperium calls it the Dropsite Massacre. The survivors called it the end of the universe.
The Siege of Terra
Seven years of civil war burned the galaxy, and it ended where it was always going to end: above Terra, aboard the Warmaster’s own flagship, the Vengeful Spirit. There the Emperor confronted His son. What passed between them no living witness can wholly tell — but Horus was struck down and unmade, and the Emperor was broken beyond mending in the doing of it.
They will tell you the Imperium won. Look around you, child of the Throne, at ten thousand years of rust and candle-smoke, and tell me what exactly was won.
Questions from the Archive
What was the Horus Heresy?
The Horus Heresy was a galaxy-wide civil war in the 31st millennium, in which Warmaster Horus — corrupted by Chaos — led fully half the Space Marine Legions in rebellion against the Emperor, culminating in the Siege of Terra.
How was Horus corrupted by Chaos?
Mortally wounded on Davin’s moon, Horus was carried into the Delphos temple on Davin at Erebus’s urging. Within, a warp ritual unmoored his spirit, and a creature wearing the face of his dead friend Sejanus showed him lies about the Emperor’s purpose — and Horus chose to take the power Chaos offered.
How did the Horus Heresy end?
At the Siege of Terra the Emperor confronted Horus aboard his flagship, the Vengeful Spirit. Horus was destroyed, and the Emperor — broken beyond mending — was interred upon the Golden Throne, where He remains to this day.