Hakari Hanazono is a first-year student at Ohananomitsu High School and holds the distinction of being one of Aijou Rentarou's first two girlfriends, alongside Inda Karane. She was born on June 22, making her a Gemini, and is known to be sixteen years old. Hakari comes from a wealthy family, being the daughter of Hahari Hanazono, and lives in a large mansion with her mother and several pets, including a large dog named Ars and a cat named Butch.

On the surface, Hakari presents herself as a prim, proper, and graceful young lady. She is generally kind-hearted and considerate towards others, showing a caring side by comforting friends like Shizuka and demonstrating a mature ability to see the good in people. She is also quite intelligent, having ranked twenty-fifth out of two hundred forty students in her midterm exams. However, beneath this refined exterior lies a personality that is far more lustful and degenerate. Hakari possesses an extremely high sex drive and is almost constantly fantasizing about romantic or lewd activities with her boyfriend, Rentarou. This secretive perverted nature is a core part of her character, earning her a reputation as a classic deredere type who is simultaneously cheerful, loving, and libidinous. She is a self-described clumsy calculative person, often devising elaborate love schemes and plans to get closer to Rentarou, though these plots frequently backfire due to her inherent clumsiness or unforeseen circumstances.

Hakari's primary motivation is her deep and abiding love for Rentarou. She is absolutely infatuated with him and seizes every opportunity to express her affection, whether through physical touch, sly seduction attempts, or grand romantic gestures. Her strong feelings can sometimes lead to bizarre behavior, such as unconsciously kissing the person or object nearest to Rentarou while lost in a fantasy about him. Despite her intense desire for Rentarou, she is committed to the harmony of the ever-growing Rentarou Family and generally accepts the addition of new girlfriends, though a hint of jealousy may occasionally surface.

Within the story, Hakari serves as a foundational member of the Rentarou Family. Her role is often that of a provocateur and a source of comedic romantic tension. She is particularly noted for her dynamic with Karane, her fellow first girlfriend. The two share a close, often competitive, but deeply caring relationship, frequently bickering or teasing one another. This bond is so strong that Hakari has, on multiple occasions and under various influences, ended up kissing Karane while thinking of Rentarou, leading to significant ship tease between them. Hakari also shares unique connections with other girlfriends; she gets along well with the gentle Yamame due to a shared love of flowers and has a close history with Mei, having grown up together as family. Her relationship with her mother, Hahari, is complex. While she respects and adores her, she is also frequently exasperated by Hahari’s own immature and perverted antics, especially after Hahari herself becomes one of Rentarou’s girlfriends.

Hakari has shown significant growth in her ability to support others. She has been instrumental in helping Karane recover her tsundere personality and has acted as a mentor and minder for some of the younger or newer members of the family. Her key abilities are not combat-oriented but social and physical. Her notable physical attribute is her voluptuous figure, particularly her G-cup bust, in which she takes great pride. Her other specialties include her elaborate, albeit often unsuccessful, love schemes and a signature, distinctive laugh often written as mwehehe or mufufu.