Ahriman the Exile thousand sons chaos space marine
The Rubricae are warriors of the Thousand Sons Legion. These forever cursed Chaos Space Marines exist only as dust, entombed by power armour. Rubricae are automatons used by Thousand Son Sorcerers as bodyguards and enforcers.
Epistolary Sabazius of the Exocists, during his secondment to the Deathwatch