Amon - Rubric of Ahriman: Following their exile into the Eye of Terror, Ahriman's love and admiration for his gene-sire had turned to hatred and contempt. When the "flesh-change" once again ran rampant amongst the survivors of the Thousand Sons and Magnus seemed to accept it, Ahriman set out to find a cure for the flesh-change himself. In his own hatred and hubris and utterly unaware of the ludicrousness of attempting to use the very energy of change to stop change, Ahriman delved into the sorcerous knowledge held in the Book of Magnus.Distilling the colossal collections of formulae, incantations and rites, and infusing the results with his own hatred of Magnus and angst at the fate of his Legion, Ahriman devised the canvas of a mighty arcane spell that would ultimately undo all the woe that had befallen his battle-brothers and thus protect them from the flesh-change for all eternity. Preliminary testing of the spell he called the Rubric generated great promise, but he quickly discovered that he lacked the raw power required to achieve permanent results.He then set to work gathering those amongst the remaining officers of the Thousand Sons who, like him, were disgusted by what had befallen their Legion and their primarch. Gathering in a fell circle around Ahriman, this cabal of sorcerers lent their power to Ahriman, who then unleashed the full power of his desperate spell.Amon was amongst those who had joined Ahriman's breakaway cabal, those who had always been the most headstrong and those with the most psychic power in the XV Legion. Those that had remained faithful to the primarch were the second-rate, the ones who had not dared to join the casting of the Rubric. The counter-sorcery affected them all, preserving less than a hundred of the Legion's sorcerers and condemning the rest, the Rubricae, to dust.The majority of battle-brothers of the Legion who lacked the psychic gift could not deal with the cataclysmic amounts of sorcerous energy which poured into them. Their flesh burned on the spot, their bodies reduced to ash inside their armour.And yet, the energies released sealed all the joints of their Power Armour as it burned their bodies. When their souls attempted to depart their ruined bodies, they found themselves trapped inside their armour; dead, yet still alive, without a body but unchanging for all eternity.In the aftermath of the cataclysm, it became clear that the Rubric had either succeeded beyond all possible expectations or failed abominably, depending on how one looked at it. Ahriman himself, along with most of his cabal, were horrified by the result. Their brethren were now as they had intended, protected from the "flesh-change," though they paid for this protection with the destruction of their physical bodies. It was only later that Ahriman saw the awful truth of what he had wrought.Instead of purging the flesh of ravening mutations, each of the Thousand Sons had been transformed into unliving automata. Magnus, angered beyond reason, assaulted the tower where Ahriman had gathered his coven. The other Chaos Sorcerers immediately knelt and abased themselves before Magnus' fury, but Ahriman remained standing, vindicated in his beliefs and utterly unrepentant.Before the Daemon Primarch could strike down his former chief librarian, the Architect of Fate, Tzeentch himself, intervened, staying Magnus' hand. Instead, Ahriman and the rest of his cabal were banished from the Planet of the Sorcerers.