Kazue Kato’s Blue Exorcist (Ao no Ekusoshisuto) is an on-going supernatural manga series.
Father Fugimoto does his best to keep his adoptive son Rin Okumura on the straight and narrow. Alas, Rin has a talent for self-sabotage. He is a stark contrast with his fraternal twin Yukio, who exemplifies self-control and diligence. If they are twins, how is that they are so different?
A supernatural encounter forces Father Fugimoto tell Rin what makes him special. Rin is the literal Son of Satan1, a potential gateway through which the evil lord could enter our world. Any other mortal host, even the purest of souls, would quickly be destroyed if Satan possessed them. Only Rin can provide a long-term home.