A misguided devotee of the Emperor
St. Ahriman the Misunderstood was an angel and witch who defied the Emperor’s decree to forswear witchcraft, instead delving ever deeper into the secrets of the Empyrean. His sorcerous mastery eventually became so great that he was able to foresee a monstrous betrayal of the Emperor from within the ranks of His own angels. When he attempted to warn the Emperor, however, he was furiously rebuked for practicing forbidden arts (the Sacramentarium implies that the prophesied heresy indeed came to pass, at terrible cost to the Emperor and those who remained loyal to Him).
Stung by his father’s rebuke, Ahriman retreated to a place called Prospero, where he rejoined the brothers of his legion of angels. The Emperor’s vengeance was not yet satisfied, however, and he unleashed another angelic legion of “Space Wolves” upon them. The siege of Prospero was apocalyptic in its scope, cracking the very surface of the earth and setting the rocks ablaze. The magics of Ahriman and a small cadre of his learned brothers, known as “librarians” of the “Librarium,” were able to shield a small portion of Prospero, Tizca, from the fury of the Space Wolves, who purged the area fighting hand to hand and street to street.
When all seemed lost, Ahriman called out to Tzeentch in desperation. He and his surviving brothers were swept to a new home, beneath the gaze of a great Eye that wept burning tears. Those of the librarium survived the translocation, but the “unworthy” – the remaining angels of the legion – were sealed within their armor, deprived of flesh and mind alike. Ahriman raged against this atrocity, but was unable to undo the terrible curse. He wanders the stars to this day, searching for the knowledge that will allow him to save his brothers.