Crúac

The ritual blood magic practiced by the Circle of the Crone. Crúac rituals always require the sacrifice of Vitae. Crúac has a singularly insidious drawback: advancement in the knowledge of Crúac comes at a terrible price to The Man, as the knowledge of Crúac's more powerful rituals serves to strengthen The Beast at the expense of The Man. (VTR: Vampire: The Requiem Rulebook, p 142)