Demon Parasite ~Akuma no You na Tenshi no Kanojo~

Inside some humans lurk mysterious parasites called Demon Parasites, granting their hosts the power to become formidable soldiers. One night, Juzo encounters Mizuki, a Demon Parasite, in the park and discovers he carries the same parasite. Thus begins his reluctant involvement in a war against monstrous foes. Can he emerge victorious? From Himeya Shop.