From Lexicanum

Captain Morleo Moriar of the Blood Angels was killed in battle in the fields of Clamorga. Unable to be revived by the chapter's greatest and most skilled Sanguinary Priests, Moriar was put into the armoured shell of a Dreadnought which was constructed by the master artificer.

Once Moriar regained his senses, he almost immediately succumbed to the Black Rage. However, Moriar survived the mental brutality of the curse and now fights alongside the Blood Angels as a Death Company Dreadnought, known as Moriar the Chosen.

It is rumoured that in his new form, Moriar has been claimed by the Red Thirst and that the Blood Angel armourers have modified his Dreadnought so that he can quench his thirst for blood. This however, is only a rumour.

Sources

• Codex: Angels of Death (2nd Edition)
• Codex: Blood Angels (3rd Edition)