The Erinyes, or the Furies, were female underworld deities of vengeance; they were sometimes referred to as "infernal goddesses". They correspond to the Dirae in Roman mythology and some suppose they are called Furies in hel, Harpies on earth, and Dirae in heaven.
According to Hesiod's Theogony, when the titan Cronus castrated his father, Uranus, and threw his genitals into the sea, the Erinyes as well as the Meliae emerged from the drops of blood when it fell on the earth, while Aphrodite was born from the crests of sea foam. According to various accounts, they emerged from an even more primordial level--from Nyx or from a union between Aether and Gaia.
Their number is usually left indeterminate. Virgil recognized three: Alecto, Megaera, and Tisiphone. Dante followed Virgil in depicting the same three-character triptych of Erinyes; in Canto IX of the Inferno, they confront the poets at the gates of the city of Dis. Whilst the Erinyes were usually described as three maiden goddesses, the Eriny Telphousia was usually a by-name for the wrathful goddess Demeter, who was worshipped under the title of Erinys in the Arcadian town of Telpousa.
The Erinyes lived in Erebus and were more ancient deities than any of the Olympians. Their task was to hear complaints brought by mortals against others and to punish their crimes by hounding the culprits relentlessly. The Erinyes are described as crones and, depending on authors, described as having snakes for hair, dog's heads, coal black bodies, bat wings, and blood-shot eyes. In their hands they carry brass-studded scourges and their victims die in torment.