Event · M31

Exodus to Sortiarius

The Exodus to Sortiarius was the flight of the Thousand Sons Legion, led by Magnus the Red, from the ruins of Prospero during the Horus Heresy. It followed the Battle of Prospero, in which Leman Russ and the Space Wolves, acting on the Emperor’s order, descended on the Thousand Sons’ homeworld after Magnus breached the Edict of Nikaea to send a warning of Horus’s treachery to Terra by sorcerous means. The attack left Prospero ruined and its Legion scattered and broken, forcing Magnus to act to save what remained of his sons. As Prospero burned, Magnus gathered the surviving Thousand Sons and used his own formidable psychic power to carry them away from the dying world. A ritual prepared with Ahzek Ahriman completed the withdrawal just as Russ was about to strike the final blow. Magnus’s physical form had been destroyed in the duel with Russ; what remained passed into the Warp as a being of corporeal warp energy. Their path led through the warp to Sortiarius, a world already known to later tradition as the Planet of the Sorcerers, where the patronage of Tzeentch is held to have prepared a refuge for the Legion. Accounts differ on the precise manner of the Legion’s arrival, but agree that the journey marked the Thousand Sons’ final severance from the Imperium they had once served. Sortiarius became the Thousand Sons’ new home in the wake of the exodus, hosting the remnants of a Legion now bound ever more closely to the Changer of the Ways. From this refuge the Thousand Sons continued to involve themselves in the wider Horus Heresy and in the Legion’s own long search for a means to arrest the slow ruin that had overtaken its warrior sons. Magnus later took his seat atop a tower on the Planet of the Sorcerers, and the world’s standing as the Thousand Sons’ stronghold endured long after the Heresy itself had passed into history.

See where Exodus to Sortiarius occurred on the galactic map during the Horus Heresy.

Open in universe