Furies/Erinyes

The Furies were chthonic (underworld) goddesses of vengeance. They persecuted oathbreakers, patricides, matricides, and other violators of divine law. Their relentless pursuit manifested in several ways, the most severe being a tormenting, self-destructive madness. The later might have personified the guilt of the criminal. They were depicted in several ways in art and poetry. The most notable depictions feature them with snakes for hair and blood dripping from their eyes.

There were a number of contradictory accounts of their origin. The most notable feature them either as daughters of the goddess Nyx (the Night), or born from the blood of the primordial god Uranus. Said blood was spilt when Uranus was castraded by his own son Kronos/Cronus/Saturn. The first act of patricide or filial disloyalty gave birth to the spirits of vengeance.