Tougen Anki: Legend of the Cursed Blood, Vol. 2 (manga)

No one ever tried to murder Shiki Ichinose on his first day of school before. But then again, he'd never attended “Rasetsu Academy,” a school designed to train Oni in the age-old conflict against the Momotarou before, either. Shiki and Jin's bickering turns bloody as a timid Homura watches her only teammates try to rip each other to shreds. But when her Oni blood awakens, the boys will have to pause their little deathmatch if they want to make it out of the forest alive…