Trazyn the Infinite

Trazyn the Infinite is a Necron Overlord, infamous for collecting rare artifacts and meddling in galactic affairs.

Official Canon
Trazyn has taken it upon himself to preserve the most exotic and valueable artifacts in the galaxy, including famous people. He posseses the head of Sebastian Thor, the husk of an Enslaver, etc. He has many doppelgangers protecting him as he travels around the galaxy, adding to his collection. He is also known to taunt his enemies, and even aided Imperial forces during the Battle of Cadia by releasing an Inquisitor from his collection, though he has made it clear that he wanted to add Roboute Guilliman to his collection as compensation.

TTS Canon
The Emperor refers to Trazyn as "Trashy the Incontinent," and wished to put in a request for someone to steal from his collection as a prank. Kitten had an inkling about a Space Marine Chapter that would fit the job perfectly. However, Kitten had forgotten what their name was, much to the disappointment of his Liege. When he finally remembered, he was stopped mid-sentence by The Fabulous Custodes who reported the Inquisition's arrival on Terra. The name was something beginning with "Blood".