They are race of giant purple reptilian birds with fangs that live in the Underworld. They attack anyone who comes near Hades' palace and they have numerous bones decorating their nests. Another race of artificial Furies are created by Electra's anger, the differences between the two is that Electra's Furies seem less reptilian, wear spiked collars, have mechanical wings and disappear into dust after one hit.
A furie appears in Once Upon a Time, invocated by the Dark OneEmma Swan to deliver Robin Hood's soul to the Underworld. In reality, the creature was only intoxicated in order to test Regina. This version of the creature was a gray humanoid, similar to a ghost with vegetative skin.