The demon in human form. An innocent girl sacrificed. Kazumi Ichinose. 16 years old. high school student. Midou Saki fell in love with him when he was an elementary school student. That was the beginning of hell. Jealousy. Obsession. Pools of Blood. Tears. Death. Common sense, words, nothing makes sense. Misfortune befell those loved by "him". Love starts with blood. This is the beginning.

(Source: Mangadex)

It's been one year since Rin moved to Tokyo for high school. He was told by the landlord of his apartment that he didn't have to pay rent if he takes care of the landlord's granddaughter, which he immediately accepted. However, that granddaughter, Mako, ended up being a 20 year old college student who is completely incapable of taking care of herself. Even so, it was love at first sight for Rin, and he's been taking care of her ever since.