Kemonotachi no Yoru

Kemonotachi no Yoru summary:

High school tough girl Aria is notorious for taking on her school’s worst bullies. But punching out jerks is nothing compared to what happens when she finds herself inexplicably drawn to the demonically possessed Sakura, a guy who would as readily rip apart his own parents as seek her healing embrace. Sakura says Aria has the power to save him, but will she be able – or even willing to?