Arai, or arae, are the daughters of Nyx, personification of Night. They are female spirits of curses, particularly those of placed by the dead upon those responsible for their death. Once an arai is cut down, their curse is released upon their killer. They are sometimes misidentified with the Erinyes, three female spirits of vengeance. The difference is that, unlike the arai, the Erinyes are controlled by Hades; while the arai are not.