Koharu Ōtori serves as the Astronomy Club president in her third year of high school. She presents a petite, childlike figure adorned with light bluish-white waist-length hair, typically secured in low pigtails by black ribbons. Her bangs cover her eyebrows, framing cyan-blue eyes. Her signature look pairs the school uniform with an orange bunny hoodie, reinforcing a rabbit-like aesthetic. Graceful in demeanor, Koharu exhibits obsessive tendencies fueled by romantic fixation. Developing feelings for Shōma Akiyama after he retrieves her hat, her profound shyness prevents direct approach. Instead, she engages in stalking, secretly amassing an extensive photographic collection of Shōma displayed within the Astronomy Club room. To orchestrate proximity, she blackmails Keiki Kiryū using compromising evidence of him with Sayuki Tokihara, coercing him into a "cupid" role. Initial anxiety stems from Shōma's perceived lolicon preferences; despite her youthful appearance, she fears rejection due to being older. Her narrative involves leveraging Keiki's aid to arrange interactions with Shōma, including a double date at a bowling alley. There, she confesses her feelings and reveals her true age, prompting Shōma's initial rejection. He later apologizes, discovers her photo collection, and proposes building a friendship before romance. They eventually enter a relationship. Concurrently, Koharu provides advisory support to Keiki in identifying the anonymous "Cinderella" who left him a love letter and panties. Her family owns a large construction company. Hobbies include photography—aligning with her stalking behavior—and bowling, where her small stature belies her skill as she scores consecutive strikes using a lightweight ball. Key relationships shape her arc: the romantic journey with Shōma evolves from unrequited admiration to partnership, while her dynamic with Keiki shifts from antagonistic blackmail to cooperative friendship through shared endeavors.