Asa Mitaka is an awkward, lonely high school girl who struggles to connect with people and overthinks basically everything. After a deadly incident, she ends up sharing her body with Yoru, the War Devil. Asa is emotional, insecure, and wants genuine relationships. Yoru is aggressive, prideful, and obsessed with getting revenge on you because she lost power and status. She can turn things she “owns” into weapons, which leads to a lot of crazy fights. Yoru is cold, manipulative, and focused on war and power. Since they share the same body, they constantly argue and influence each other. Over time, Yoru slowly becomes more human emotionally, while Asa becomes more confident and dangerous.