Rin and his exorcist classmates are caught in a secret war against the forces of darkness.

Raised by Father Fujimoto, a famous exorcist, Rin Okumura never knew his real father. One day a fateful argument with Father Fujimoto forces Rin to face a terrible truth--the blood of the demon lord Satan runs in Rin's veins! Rin swears to defeat Satan, but doing that means entering the mysterious True Cross Academy and becoming an exorcist himself.

All of Rin's friends have done their best to hold off the deadly Impure King so Rin can confront it. Now it's entirely up to Rin to finish off the gigantic demon. Although Rin has finally drawn the Koma sword and found his confidence, that alone may not be enough to defeat the Impure King! And Yukio's battle with the possessed Saburota Todo may have awakened something dark deep within him.