Imperial Armour 7: The Siege of Vraks, part 3 (2009), p88 — Epilogue

Of the other traitors to the Imperium, most were killed, including the Apostate Cardinal Xaphan himself. Deacon Mamon, the Cardinal's closest advisor was also assumed killed on Vraks, although there has been no official confirmation. If, as rumoured, he actually did attain the honour of daemon prince, then it may be that he is now a creature more 'of the Warp' than of the material universe. His name has been added to the Grimoire of True Names in the event of a subsequent summoning.