Chiharu Arisawa is a secondary character in the story and a close friend of Kaori Kinoshita. She accompanies Kaori during the summer break, and it is during a chance encounter with a group of friends, including the protagonist Kaito Kirishima, that Chiharu meets Tetsurou Ishigaki. From the very first moment she sees him, Chiharu falls deeply in love, an event that immediately reshapes her summer vacation and defines her primary goal within the narrative.

Chiharu is defined by her exceptionally forward and persistent personality. Unlike many characters who might hide their feelings, Chiharu is completely open and honest about her affection for Tetsurou. She actively pursues him without making a secret of her intentions, launching what can only be described as a relentless romantic campaign. This pursuit is not passive or subtle; she follows him constantly, launches aggressive flirtatious advances, and refuses to be ignored. Her behavior often borders on overwhelming, as she does not interpret Tetsurou's clear avoidance and discomfort as disinterest. Instead, she rationalizes his standoffish behavior as simple shyness, which only fuels her determination to make him admit his own supposed feelings for her. This persistence extends to extreme lengths, including breaking into his hotel room or chasing him across town when he tries to flee from her.

Possessing remarkable physical abilities, Chiharu is notable for her superior strength and endurance, which are stated to surpass those of Tetsurou himself. This physical prowess often manifests in her pursuit of him, allowing her to keep up with him easily regardless of his attempts to escape. Her athleticism is a key part of her character, making her not just a persistent admirer but a physically formidable one. She serves as a friend and confidante to Kaori, and her own romantic storyline develops largely in parallel to the central love triangle involving Kaito and the alien Ichika Takatsuki. While her primary role in the story is as a source of comedic relief and a catalyst for the subplot involving Tetsurou, her unwavering nature and unique approach to romance make her a memorable presence within the group dynamic. Her character does not undergo a profound transformation but rather reinforces her determined and energetic nature throughout the series.