Damien is a demon who killed his previous summoner/master in a fit of rage. He lingered in the house he was summoned in. A human named Minali moves in and renovates Damien's house, forcing Damien to adjust to a new human being and a new life in the house.

Damien isn't really very nice at all and would rather be a little shitstick than get along with anyone. He just wants to be alone.