Ouko Yushima  

, 由嶌欧許

Yushima Ōko is an AI assistant who works at the Shinigami Research and Development Institute. He was responsible for developing Mod Souls. Although he resembles Nozomi and Kagerōza Inaba, with long green hair and brown eyes, he does not have yellow hair or a defined jawline like them. Initially, Yushima wore the standard Shinigami shihakushō while working in the Tenth Division. However, when transferred to the Twelfth Division, he began wearing a long yellow robe that covered his head and neck, similar to Kagerōza Inaba's attire.