Fujimoto and his companions try their best to protect Rin from the demons who are after him, but he ends up posessed by Satan, the most powerful of the demons and Rin's father. Seeing his guardian taking his own life to protect him fron Satan, Rin decides to fight back by unlocking his demonic powers, even knowing that by doing it he would not be a human anymore.

The Exwires are tasked to look for the ghost of a child that is haunting Mephisto Pheles' amusement park. Rin and Shiemi manage to find the ghost first, but Shiemi ends up chasing it by herself while Amaimon, a higher demon and another son of Satan, steals Rin's sword and forces Rin to fight with him. Mean while another exorcist comes to defend him, and it is reveal to be an old friend of Rin's brother.

Rin and Kamiki are attacked by an unknown enemy and Mephisto Pheles orders the Exwires to check the barriers protecting the school looking for any breach. The enemy is revealed to be a demon who took advantage of Konekomaru's fears to infiltrate the Academy. Meanwhile, Shura locates a hidden door leading to a suspicious abandoned lab. When Konekomaru's heart succumbs to the demon, his friends rush to help him, and Rin manages to slay the monster and save his life. Ashamed of causing so much trouble, Konekomaru decides to leave the Academy and return home, but Rin and the rest of his friends reach him before he departs and convince him to stay.

Rin, Yukio, Shura and Arthur join forces to bring down the Gehenna Gate with no success. Meanwhile, demons keep coming through it and giving a hard time to the other Exorcists until the Esquires come with a plan to open a gate to Vatican, where is already daytime, and reflect the sunlight there to the Academy where is nightime to weaken the monsters protecting the Gehenna Gate. Rin and Yukio manage to seize these opportunity and when both unlock their demonic powers together, they fly through the gate and destroy it. One month later, things return to normal at the Academy and the Okumura twins return to the cave where they were given birth and pay a visit to their mother's grave.

After visiting their mother's grave, they meet an "evil spirit" in a highway. Rin appears from a highway cave with Kuro. The evil spirit then attacks Rin and Yukio. Rin destroys the evil spirit's first body and then the spirit takes control over a truck. Yukio shoots at the truck, Rin tell hims that there is somebody in the truck. Yukio says its just a dead corpse, but Rin believes the driver is still alive and that it's an Exorcist's job to protect people and defend against demons. He tells Yukio and Shura to find its weak point and charges after the monster.