Kami-sama Dolls

Kyouhei, after moving away to Tokyo from his old town to get away from the events that happened, is on a goukon with his friends, including his old neighbor, Shiba. After drinking for a whole night, he and Shiba discover a dead, bloody, body in the elevator. He is told by his younger sister, Utao with her Kami-sama Doll, that Aki, an old friend, and his Doll, are the culprits responsible. (Source: Fate)