Rubric of Ahriman
The Rubric of Ahriman was the cataclysmic spell cast by the Chief Librarian Ahriman of the Thousand Sons Space Marine Legion and his Cabal, which transformed the majority of the Thousand Sons into soulless automatons.
Prior to unification with their Primarch, in the earliest days of the Thousand Sons' history, the Legion was constantly in turmoil, faced with the threat of mutation. When Magnus was found, the legion was afforded some stability and his training allowed control, and use of, their newfound powers. Despite these improvements all was not well. It came to a head when the Legion betrayed the Emperor and joined the forces of Chaos during the Horus Heresy. The Thousand Sons adopted the Chaos God Tzeentch, Changer of Ways, as their patron. Mutation began to spread rapidly, especially after Magnus's promotion to Daemon Prince.[1a]
Ahriman and his conclave of the Legion's mightiest sorcerers decided to stop the mutation for all time. They laid the foundations for a great spell that they believed would make their warriors pure for the rest of time. The actual spell unleashed was so powerful that even the Daemons of the Warp shied from it. The Planet of Sorcerers was engulfed in a storm of blue and yellow lightning, striking down every Marine on the planet. Eventually Magnus intervened and stopped the spell.[1a]
The spell both succeeded beyond Ahriman's wildest dreams, and was an incredible disaster. Less than 100 of the Thousand Sons who possessed psychic powers had them greatly augmented ; however, the majority of the Legion's Marines, who had little or no psychic ability, had their physical bodies reduced to dust, trapping their spirits in their armour, the joints of which were sealed magically and allowed the spirits no way of escaping. Thus were the Thousand Sons rendered immune from mutation, and also damned for eternity.[1a] Since Ahriman's spell was cast, the Thousand Sons' armies have been composed of these Rubric Marines, which are dependent on nearby Sorcerers to guide and motivate them.[1b]
- 1: Codex: Chaos Space Marines (4th Edition)
- 2: Index Astartes III, [Needs Citation]
- 3: Battle of the Fang (Novel), Chapter 3, p. 63