Easily breaking through all defenses, Amaimon reaches the room where Rin is being held and Mephisto convinces the Grigori to agree with his plan. Using the reforged Demon-Slaying Blade brought by his classmates, Rin defeats Amaimon and the Grigori decides that he has six months to pass the Exorcist authorization exam, thus he begins a special training to learn to control his flames. Despite they helped Rin by having his sword fixed, some of his classmates still has some mixed feelings about him after learning of his connection with Satan, the most awkward of them being Konekomaru, who is approached by a dark presence attracted by his fear.

Ernst takes over as the True Cross' newest leader and appoints Yukio as the new Paladin. Armed with special weapons that drain the blood of the demons killed with them, the exorcists take part in a widespread crusade to erase all demons from Assiah. Rin and his friends start questioning why the order decided to take such extreme measures, but Yukio is determined to accomplish his task as Ernst claims that it is all part of their plan to destroy Gehenna, and with the Demon world vanquished, both he and his brother would become completely human again. However, Ernst's real objective is revealed when he uses Rin as a human sacrifice to bring Satan to the Human World, using Yukio's body as a vessel.