>>537777718
Denathrius is one of the Eternals, the gods of the Death pantheon and his job is to oversee the penance of evil souls.
Essentially, he's the king of Purgatory.
Except Purgatory is staffed by vampires who drain souls of their animals generated by their evil thoughts.
People liked him a lot and thought he was a much more convincing villain than... really anyone since Garrosh.
Then they revealed that the Nathrezim were his creation that he sent to be his spies in every other cosmic force like the Legion and the Light and the Void and so on and he has some master plan that they've yet to actually write yet.

IE, Denathrius is charismatic WoW Dracula wielding a yandere sword that they're saving for a rainy day.