Empousa is a species of monsters commanded by Hecate.
Empousa was the beautiful daughter of the goddess Hecate and the spirit Mormo. She feasted on blood by seducing men as they slept before drinking their blood.
Empousa is pictured as wearing brazen slippers and bearing flaming hair. Her name was said to mean "one-footed". This is because they are a one-legged hybrid, with a donkey's leg and a bronze prosthetic leg. Vampires are they're distant cosins.
There is species of Hecatean demon called an empouse or empousa. The empouses were sent by Hecate to guard roads and devour travelers. According to some, empousae ran and hid, uttering a high-pitched scream, at the sound of insults.
The empousae are best known for their appearance in Aristophanes's The Frogs, in which they scared Dionysus and Xanthias on their way to the underworld.