Shura no Hakoniwa

Utsuro is a creature that consumes a type of bioenergy called "nectar," which is found only in young girls. Iruka Natsumi is part of Hyakkaen, a group that constantly battles Utsuro. She fears being eaten by one. A girl named Sagara Asuka arrives and announces her goal to eliminate all Utsuro. She proposes living with Natsumi until the latter turns 19, when her nectar will vanish. Asuka demonstrates great power in fighting Utsuro but carries a hidden secret.