Circe is a witch of Caucus, and the sister of Pasiphae
At some point in the past, Circe had a husband and a home, but Pasiphae destroyed her life, killed her husband and banished her to live in cave far away.
Circe later began offering her services near Atlantis, promising to give all at the price of there most important posssion. This attracted Hercules who was desperately in love with Medusa. Giving Circle his most prized possession, the last link he had to his father. Circe gave him a powerful enchantment, the Song of the Sirens which made Medusa fall for Hercules. However a few days later, the spell turned on her, making Medusa very ill and on the verg of Death.
Unable to find a way to cure her, Hercules returned to Circe and tried to force her to undo the spell. However using her magic, Circe overpowered Herclues, and mocked him, declaring he was mearly a pawn in her plan. She then revealed she was after Jason, who she knew would come for his friend. Using her magic she turned Hercules into a pig.
Later seeing Jason and Pythagerous arriving, she used her magic to summon a monster that attacked Pythagerous. Jason managed to kill it, but he was forced to face Circe alone. Circle revealed her story, and told him they were allies and she would undo the spells, for the price of Jason killing her sister. Unable to leave his friends to there fates Jason reluctantly agreed. Using her necklass, Circe bound it so Jason was unable to break the deal. She then revealed her sister was Pasiphae. True to her word she undid her spells, but left Jason forced with an agreement he did not want.
Circe later appeared in Jasons dreams telling it was time for him to furfil there deal and kill Pasiphae, giving him three days or she would kill them all. Jason found Circe's mark burned into there table as a symbol of what they had to do. They formulated a plan, but at the last minute Jason found he couldn't bring himself to kill Pasiphae. Instead he went to face Circe, offering himself and asking her to spare his friends. Circe refused and telekinetically tossed two spears at him, however Jason managed to evade them. Drawing his sword he jumped at her, but Circe teleported out of the way. She then created the illusion of two extra Circe's. Picking the wrong one Jason tossed his sword, but it went through the illusion. Circe threw two more spears, Jason again dodged, but this time was cut. All the Circe's laughed and taunted him, only for Jason to hurl his knife at her, stabbing her in the chest. He revealed that he knew, as she was the only one that cast a reflection in the pool. As a last act of definace, Circe cast a spell and tossed several dragons teeth into the ground, before dying. Out of the ground sproated three Skeleton warriors, however Pythagoras and Hercules arrived and between the three of them they managed to destroy them all.