Shiga Hime

Shiga Hime (屍牙姫, Shigahime) is a Japanese manga series written and illustrated by SATOU Hirohisa.

Plot
Osamu is living a peaceful life, having a girlfriend, not carrying much about school, all that changes when he follows a boy named Souichi to Miwako's mansion. Now he is thrown into a world he would have never imagined and is trying to get back to normal life, while being a familiar to Miwako and bringing her fresh hearts...