Blue Exorcist (2011)

Season 1: Episode 8

Still troubled after her friend Paku decides to leave the Exorcist lessons, Kamiki gets involved in a fight with Bon and the entire class end up punished by Yukio. Just after Yukio leaves for a mission, the students are attacked by another ghoul and while trying to help the others, Rin learns that the monster was sent by one of his teachers who wanted to confirm that he is the son of Satan.