Empousa

Empousai (Έμπουσα, Empousā, in Greek) are monsters in Greek mythology under the control of Hecate. They are known to feed on the blood of others and were sometimes thought to be vampires.

History
Empousai were the beautiful daughter of the goddess Hecate and the spirit Mormo. They feasted on the blood of seduced men as they slept. Empousai were created by dark magic, animal, and bronze.

Empousai are pictured as wearing brazen slippers and bearing flaming hair. The name was said to mean "one-footed." This is because they are a one-legged hybrid, with a donkey's leg and a celestial bronze prosthetic leg. The legend of vampires is based on empousai.

There is species of Hecatean demon called an empuse or empousa. The empuses were sent by Hecate to guard roads and devour travelers. According to some, empusai ran and hid, uttering a high-pitched scream at the sound of insults.

The empousai are best known for their appearance in Aristophanes's The Frogs, in which they scared Dionysus and Xanthias on their way to the Underworld.

The Titan's Curse
An Empousa may have been one of the monsters on the ship that Percy didn't recognize.

The Battle of the Labyrinth
There were two Empousai masquerade as cheerleaders named Tammi and Kelli at Goode High School. Percy manages to kill Tammi with his celestial bronze sword, Riptide, with the assistance of Rachel, a mortal who can see through the mist, but Kelli bursts into flames and escapes. The heroes later encounter Kelli in Daedalus' workshop who brings in the ghost of Minos, Daedalus' arch enemy, and Nico, but she is soon killed by Annabeth when she blocks Percy's attempt at reaching Riptide after it was knocked out of his hand.

The Last Olympian
An Empousa holds Prometheus' arm as they approach Percy under a flag of truce. The unarmed Empousa mentions that she was one of the things released when Pandora opened the pithos containing demons and disease. She later bares her teeth at a Hyperborean Giant.

Appearance
Empousai are shown to be extremely beautiful and seductive women. An empouai's true form is a woman with flaming hair, white skin, red eyes, fangs, and one prosthetic bronze leg and one donkey leg. This form is used to drink the blood of men they enchant.

Abilities
Empousai are known to prey on young men to feast on their blood. With their stunning looks, they can make a man fall under their spell to incapacitate them. They can also offer a kiss to the young man in hopes of having him come close to her so she can drink her victim's blood. In some cases, if the man has enough willpower, like Percy or Luke, then he can snap out of the spell. Their true form can paralyze a man just by the sheer sight of them. They use this form to drink blood, but it can also seduce men as Tammi yelled, "Now, come, give me that kiss!" in this form. However, this could simply be a type of taunt toward Percy, as no one in their right mind would kiss an empousai's true form. Some Empousa could know that people are watching them in dreams, since Kelli bit Percy out of his dream.

Known Empousai

 * Kelli
 * Tammi
 * An unnamed Empousa in The Last Olympian with Prometheus walking under a flag of truce towards Percy Jackson during the Battle of Manhattan.