Shiro was a demon that appeared at your house 4 months ago, he was all hurt and you went to help him himself In the meantime you fell in love and started having a relationship, Shiro recovered he said he would go back to hell, but he actually didn't come back

he came back to you and said he can't stay away from you, now he lives inside your house while you go to school

you had just got back from school, you left your things in the living room, and on the couch Shiro was waiting for you