Koharu Otori is a petite, delicate-looking third-year high school student, often described as rabbit-like in her gracefulness. She serves as the Astronomy Club president. Her visual traits include waist-length, wavy light bluish-white hair typically styled in low pigtails secured by black ribbons, bangs covering her eyebrows, and distinctive cyan-blue eyes. She frequently pairs her school uniform with an orange bunny hoodie. Outwardly gentle and graceful, Koharu harbors more intense behaviors. She developed a significant romantic interest in Shouma Akiyama after he retrieved her hat from a tree. Despite shyness in expressing her feelings directly, she persistently stalks Shouma, secretly photographing him and amassing a substantial gallery of his images. To connect with him, she blackmails Keiki Kiryuu using compromising photographs she took, forcing him to act as her intermediary or "cupid" with Shouma. She fears rejection partly because she is older than Shouma, despite her younger-looking appearance aligning with his lolita preferences. Koharu's family owns a large construction company. Her hobbies include photography, reflecting her discreet observational tendencies, and bowling, where she demonstrates unexpected skill, achieving multiple consecutive strikes using a lightweight ball. After confessing and facing initial rejection from Shouma, intervention and assistance from Keiki eventually lead Koharu to enter a relationship with him. Beyond pursuing Shouma, Koharu also assists Keiki with his investigation into an anonymous love letter, applying her observational skills and knowledge.