Ao no Exorcist

Rin Okumura grows up believing he is an ordinary troublemaker raised by exorcist Shiro Fujimoto. His life collapses when demons begin pursuing him and he learns the truth hidden since birth: he is the son of Satan, ruler of Gehenna, and the blue flames inside him are proof of that bloodline.

After losing Shiro, Rin rejects Satan and chooses to become an exorcist himself. At True Cross Academy, he trains beside other aspiring exorcists under the watch of his gifted twin brother Yukio, all while hiding a secret that could turn his new companions against him if his demonic power is exposed.