Rin Okumura is a seemingly ordinary delinquent until he discovers he is the son of Satan, the ruler of Gehenna. After his foster father, Father Shiro Fujimoto, dies protecting him, Rin makes a life-altering decision: he will not join his biological father, but instead become an Exorcist to "beat the hell out of Satan." Enrolling in the True Cross Academy, he begins training alongside his genius twin brother, Yukio. However, as the secret of his birth leaks and the organization "Illuminati" rises, Rin must navigate a world of prejudice, demonic warfare, and a hidden history—the Blue Night—that explains why he was born and what his true purpose in the coming apocalypse might be.