Blue Exorcist Vol. 12 (manga)

As the True Cross Academy festival reaches its peak, trouble is brewing. While Izumo confronts Nemu Takara, Rin and the rest of the Exwires race to find her. The betrayal they discover and the tragic details of Izumo's past will shake them to the core and herald the beginning of an all-out war between the Illuminati and the Knights of the True Cross!