Furies - the Erinyes

The Furies were the three goddesses of vengeance: Tisiphone (avenger of murder), Megaera (the jealous) and Alecto (constant anger). They were also called the Daughters of the Night, but were actually the daughters of Uranus and Gaea. Another name for them is the Erinyes. The Erinyes live in Erebus and are more ancient than any of the Olympians. Their task is to hear complaints brought by mortals against the insolence of the young to the aged, of children to parents, of hosts to guests, and of householders or city councils to suppliants—and to punish such crimes by hounding culprits relentlessly. The Erinyes are crones and often described as having snakes for hair, dog's heads, coal black bodies, bat's wings, and blood-shot eyes. Their victims die in torment.

A victim seeking justice could call down the curse of the Erinys upon the criminal. The Roman Furies were originally nothing but a personification of curses pronounced upon a guilty criminal.