Ao No Exorcist (Blue Exorcist)

Episode 3:Brothers

Rin is enrolled at the True Cross Academy by Mephisto, revealed as the academy's chairman. During the class assembly, Rin is surprised to know that Yukio is the freshman class representative. After some exploration around the vast campus, Rin is later given a key from Mephisto to gain entry to the cram school to become a Page, which is a title for an Exorcist in training. Rin becomes shocked to know that Yukio will be one of his teachers, having alreadybeen a prodigiously graduated Exorcist, meaning that Yukio was aware that Rin was a demon this whole time. Rin, demanding to knowwhy Yukio kept this a secret, accidentally shatters a blood-filled capsule onto the ground, releasing hobgoblins in the classroom. While taking down the hobgoblins with his guns, Yukio voices his hatred towards Rin for being atfault for allowing Satan to possess Shiro in the first place. Rin uses his powers to take down a giant hobgoblin after Yukio hesitates to shoot Rin. Yukio recalls Shiro telling him to protect Rin, which motivated him in becoming an Exorcist. Rin is further dismayed to learn that Yukio is his roommate, but really more like a warden.