Pupa

Summary:

This story follows Utsutsu and Yume Hasegawa, a boy and his little sister who find themselves essentially all alone after the death of their mother and the negligence of their father. One day, they meet a woman who warns them of red butterflies, but her warning is not taken seriously. Then, Yume sees a mysterious red butterfly and her body undergoes a strange metamorphosis into a creature that eats humans. Utsutsu is also affected by the butterfly, but instead of turning into a monster, he gains the ability to immediately heal from any wound, making him a convenient target for his sister. Utsutsu struggles to find a way to restore his sister.