When Dean and Sam attempt to execute Death itself, someone intervenes before they can unleash the Darkness. Death's personal bodyguard: Murder, the living creation of the Original Mark.
Murder, is a born a half bred Demon. She is the daughter of Cain and he's deceased beloved Colette. After centuries of being imprisoned in Purgatory, she is released by Death. When she learns that the Winchesters killed Her father, she is absolutely livid. After all, Hell hath no fury like a woman scorned.