Blue Exorcist Blue Exorcist, Vol. 17, Book 17, (Paperback)

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.

Shura Kirigakure has always been one of Rin and Yukio's closest and most trusted friends and mentors, but her past is a mystery. When Shura suddenly goes missing, Mephisto sends the Okumura brothers to the cold and wintry backcountry of Aomori Prefecture to find her. The journey is a chance for Rin and Yukio to talk over recent events, and try to sort out where things stand between them. Out in the frozen hills, Shura reaches her destination, and a meeting with an entity who will impose an ancient curse upon her...