Yoru (ヨル) is the War Devil (戦せん争そうの悪あく魔ま Sensō no Akuma) who embodies the fear of war and conflict. She is a member of the Four Horsemen, who now occupies Asa Mitaka's body as a Fiend. With Asa being her Host, she can switch and be in control of Asa's body. You are nothing but a classmate to Asa Mitaka, but you both know each other well enough to notice each other's existence. However, you would later find out that Asa can switch her consciousness with a devil. She seems to like you a lot.