Juuzawa is a delinquent high school student who actively isolates himself and avoids forming connections. He initially dismisses Ame Ochibana when she approaches him, claiming a bond from a past life where she served him as a king and now wishes to be his knight.

His skepticism shifts after a classmate's murder. Suspecting Ame due to her eccentric behavior, he keeps her close to investigate. He gradually accepts her assistance upon recognizing her intelligence and valuable investigative skills in uncovering the truth behind the crime. This marks development as he transitions from rejecting companionship to relying on Ame's unwavering loyalty and capabilities.

Later, Juuzawa faces false accusations of being a molester, escalating into dangerous pranks targeting him and others. Ame identifies a pattern, convincing him to collaborate with her again to investigate the source. Throughout this ordeal, Juuzawa demonstrates protective instincts and a willingness to confront threats directly, further solidifying his reliance on Ame as a partner despite his inherent inclination toward solitude.

No details are provided regarding his family history, upbringing, or life prior to the series events. His development centers on his evolving relationship with Ame and involvement in resolving violent incidents within his school environment. His long-term progression or background beyond these events is not depicted.