List of characters in the Camp Half-Blood series
Medea - A sorceress and granddaughter of Helios that Jason, Piper, and Leo encountered in "The Lost Hero." She is shown as the head of a mall in Chicago that Jason, Piper, and Leo visit. She begins to show the demigods her stock of magic objects and potions, but becomes angry when she hears Jason's name (as he is named after the hero that betrayed her). It quickly becomes evident to Piper that Medea is an agent of Gaia, and the one who Hera had warned them about. Jason and Leo however are entranced by the magic in Medea's voice who tells them to attack and kill one another. Piper managed to bring the two to their senses and they blew up the mall. Medea shouts that she will not be abandoned again causing the three to quickly leave before she makes another attempt to destroy them.