Wicked

Sawyer Thropp is a young warlock, and extremely powerful. She is part of the Wizard's order, a group of downworlders allied with the Clave, led by the Wizard. When Sawyer turns against him, people start calling her the Wicked Witch of the West. Two years later, Alec Lightwood is tasked with finding her and killing her, and of course, Jace, Clary, Magnus, Izzy and Simon will help.