Erinyes

The Erinyes, whom the Romans called the Furies, are three goddesses who avenge the shedding of kindred blood. Hesiod says they were born from the drops of blood that fell upon Earth when Uranus was castrated; later tradition names them Alecto, Megaera, and Tisiphone. Snakes twine in their hair and they carry torches and iron whips as they hunt those who murder kin or break oaths, pursuing by day and night, driving their prey mad, and never relenting until death.

In the Eumenides, the closing play of Aeschylus's Oresteia trilogy, they form the chorus: they chase Orestes to Athens for killing his mother, Athena convenes a court on the Areopagus to try the case and casts the deciding vote for acquittal, and then persuades the goddesses to accept perpetual cult in the city under the new name Eumenides, 'the Kindly Ones,' with a shrine in a cave at the foot of the Areopagus. Athenians preferred not to speak their true name, calling them the August Goddesses. The play, staged in 458 BCE, stitched the old law of blood for blood to the new order of the civic court, one of the earliest trial scenes in Western literature.