One of Rentarou's girlfriends. She possesses a captivating figure yet maintains impeccable conduct. In reality, however, she is a calculating schemer—though at times, her mind becomes so consumed by romantic fantasies that she gets carried away by her own plots. Deep down, she is earnest and unfailingly considerate toward everyone, not just Rentarou. Her mother is Hahari.

One of Rentaro's girlfriends. She is an "all-around" tsundere girl whose catchphrase is "It's not like I'm [doing/being]...!" Although she has a tough, guarded personality, she also possesses a dependable, big-sisterly nature. While she often plays the straight man—acting as the voice of reason—she also has a surprisingly sensitive side.

One of Rentarou's girlfriends. A library committee member who loves reading. Petite and quiet, she possesses an adorable, small-animal-like charm and is a hard worker. She used to struggle with conversation and would communicate by pointing to passages in her favorite books, but thanks to a text-to-speech app provided by Rentarou, she is now able to hold conversations while making eye contact.

One of Rentarou's girlfriends. She is gifted with both beauty and brains, achieving perfect scores in every subject. She prioritizes efficiency in all things; before meeting Rentarou, she even dismissed romance as a "waste of time." Although she appears cool and composed because she rarely shows emotion on her face, she is surprisingly warm-hearted. Her focus on efficiency can sometimes lead her to take bold actions.

One of Rentarou's girlfriends. A high school senior who loves developing medicines. Although she is 18 years old, the side effects of a failed "immortality elixir" mean she usually lives in the form of an eight-year-old. She has an innocent and cheerful personality; while she often causes chaos by concocting various medicines, she always deeply cares for her friends.

She is one of Rentarou's girlfriends and Hakari's mother. She has a weakness for cute things. Although she once disapproved of the group's romantic relationships, now that she has become one of his girlfriends herself, she pours immense affection not only onto Rentarou but onto all the other girls as well. While she sometimes lets her behavior go completely uninhibited, she possesses both mature allure and a maternal nature, serving as a mother figure for the entire family.

One of Rentarou's girlfriends. A third-year junior high student whose trademark look features a hoodie and headphones. She has a personality that causes her to associate any word with food, and she gets irritable the moment she's hungry. However, she also has a sweet, earnest side—feeling down when she reflects on how she behaved while famished.

One of Rentarou's girlfriends. A third-year junior high student whose trademark look features a hoodie and headphones. She has a personality that causes her to associate any word with food, and she gets irritable the moment she's hungry. However, she also has a sweet, earnest side—feeling down when she reflects on how she behaved while famished. She is loyal to the Hanazono and her boyfriend.

One of Rentarou's girlfriends. A boyish and stoic member of the girls' baseball team. Whether she's practicing baseball or going about her daily life, she tends to push herself to grueling, reckless extremes. Although those around her often try to stop her, she is a massive masochist and actually enjoys it.

One of Rentarou's girlfriends. A dazzlingly beautiful second-year high school student. She possesses a strong sense of self-love and reacts with genuine delight when praised. Driven by an intense obsession with and desire to explore beauty, she is a hard worker who never neglects the effort required to maintain her stunning appearance.