Koharu Shiihara is a main character in the anime Celestial Method. She lives in Lake Kiriya City, where an unexplained flying saucer has hovered in the sky for seven years. Her family runs a local souvenir shop catering to the saucer, and Koharu works there as a poster girl. She is one of the childhood friends who originally gathered to make a wish that inadvertently summoned the saucer.

Koharu is gentle, kind, and deeply caring, though she is also somewhat airheaded and clumsy. She values harmony within her group of friends and strongly dislikes conflict, feeling distressed whenever they argue. Rather than confront issues head-on, she uses her soft and soothing demeanor to ease tensions and tries to support her friends in her own quiet way.

Her main motivation is the happiness and unity of her friend group. She is a loyal supporter of Nonoka Komiya, standing by her side when others are angry about the past. She also displays fierce loyalty to Yuzuki Mizusaka, reassuring her that she is always on her side. These relationships define her role as the emotional heart and peacemaker of the group.

Koharu does not possess any supernatural powers. Her notable ability is her emotional intelligence and steadfast loyalty. Over the course of the story, she develops from a passive peacemaker into an active participant in healing the group’s fractured bonds, providing a crucial foundation for reconciliation and growth.