Blight is a capricious psychotic nameless white mask.
The nameless white masks individuals are war surgeons were effectively mercy killers. Of the surgeons that were abducted by the Lord of Blood none were able to tame the accursed blood. None but Varré, that is; though he was an exception. They are  invaders that wear the War Surgeon Set, taking on the appearance of White Mask Varre. They focus on blood loss attacks, using a dagger as well as the Swarm of Flies incantation.