Rengoku no Cartagra

Transfer student Yuuki Yuriya does not participate in church services or Bible study, so he is rumored to be the culprit behind the recent "demonic ceremonies" occurring at Seirei Academy. Truthfully, he has never before been involved with the supernatural—until one evening, when he witnesses an unknown girl jump from the school rooftop. Next to her bloody corpse, he finds a mysterious book containing instructions he feels compelled to follow. Yuuki is shocked when he successfully summons Demon ...