Blue Exorcist: Kyoto Saga

Rin Okumura bears the curse of being Satan's illegitimate son. He decides to hide his origins and enrolls at the Exorcism Cram School, a training institute for exorcists located on the True Cross Academy grounds. During an attack by Amaimon, the King of Earth, his identity as the Son of Satan is revealed. His friends are terrified and start to distance themselves. Then someone steals the Left Eye of the Impure King that had been sealed away in the deepest part of the academy. Rin and the others find themselves in an unexpected crisis.