pupa

Utsutsu Hasegawa has only his younger sister Yume left, and he has built his life around protecting her. A swarm of red butterflies passes over the two of them, and both are infected by a virus called Pupa. Yume's body turns into a creature that hungers for human flesh, while Utsutsu's gains the ability to heal any wound and regrow whatever he loses. So he feeds her the only meat she can take without killing anyone: his own, over and over.