Everyone's boyfriend. He has a puppy-like face and is such an incredible gentleman that he's perfectly wholesome. He values his girlfriends more than his own life and spends money on them without hesitation. He switches between polite and casual speech and understands all the strengths and weaknesses of his girlfriends. He loves every single one of them equally. Both of his parents are teachers; he's not wealthy, just extremely wholesome.

Hanazono Hakari: Ultra mega-dere. Uses polite speech. She's a pervert. Inda Karane: Ultra tsundere. Uses casual speech. Yoshimoto Shizuka: Speech impaired. Communicates via phone TTS. Loves books. Eiai Nano: Extreme efficiency seeker. Calls people by their full names and uses casual speech. Yakuzen Kusuri: Makes drugs. Due to side effects, she looks like an 8-year-old and has the mental age to match. When she takes the antidote, she becomes 18. Ends sentences with "-nanoda." Hanazono Hahari: Hakari's mother. Has no dignity and loses her mind over cute things. Super rich, lives in a mansion, and runs several factories. Basically a pervert... Haraga Kurumi: A girl who is literally always hungry. Polite (only when eating). Has incredibly fast digestion. Meido Mei: The Hanazono family maid. Keeps her eyes closed. Has rainbow pupils. Devoted to Hahari. Adds "-sama" to every person or object. When she gets serious, her eyes occasionally open. Always has a smiling face. Sutou Iku: A baseball-loving extreme masochist. Even if she's just uncomfortable, she likes it; if she's in pain, she loves it, saying "It hurts..♥" Utsukushisugi Mimimi: A senior who values beauty above all else. Ends sentences with "-desu wa." Puts in immense effort for the sake of beauty.

Kakure Meme: Hides her eyes with her bangs. If she gets embarrassed, she leaves a doll behind and vanishes. Actually incredibly beautiful. Iin Chiyo: A class president who values correctness, but if she takes off her glasses, she cries thinking of her mother. She views the 18-year-old version of Kusuri as her mother. If something isn't right, she fixes it while making a "Ugh..." sound. Yamato Nadeshiko: A Japanese teacher who uses broken English. Loves America. Uses English that ignores all grammar. Cowboy look. Loves freedom. Yasashiki Yamame: A 2-meter-tall gardening club student who is afraid of fire. Ends sentences with "-yoo." Says "[This] is also alive-yoo..." to all living things. Can tame animals that don't usually trust humans. Momi Momiji: An expressionless massage therapist junior. Only uses polite speech. Always kneading something. Yakuzen Yaku: Kusuri's grandmother. Actually 89 years old, but looks 8 years old due to a drug. Ends sentences with "-nanonijya." The immortality drug was a near-success failure, so she can never return from her 8-year-old form. Her mental age remains 89. Has war experience. Torotoro Kishika: A Kendo club senior, but if she's patted or treated like a baby, she becomes pampered and her mental age regresses to an infant. Values chivalry highly. Kedalui Ashi: A low-tension gyaru. Replaces "shi" with "chi" and "gwi-yeop-da" (cute) with "gyeop-da." Always has a faint smile. Says she feels strange when she shares the same emotions as others. Constantly says "Gyeop-da." Nakaji Uto: A chuunibyou who looks like a bard, wearing adventurer clothes and using adventurer speech 24/7. Always says obvious things as if they're profound. Terrible at instruments and music. If genuinely flustered, she acts like a normal 8th grader. Meido Mai: A maid who admires Mei and considers her an older sister (not biological; the kanji for their surnames differ). When scolded, she gets spanked by Mei. A tsundere who also likes Rentarou.

Bonnoji Momoha: An ethics teacher with strong desires for alcohol, gambling, and sex. She can endure the inevitable, but if someone tries to follow her or be like her, she often says "You must never become like me!!" like a true ethics teacher. Baio Rin: Incredible at the violin. Loves violent things; when she sees violence or cruelty, she gets excited and says "Violin-shite!!" Hifumi Suu: A fastidious girl with glasses who goes crazy for numbers. Kaho Eira: A college student who does Capoeira, but if it's something that can't be solved physically, she rolls around saying "[This] can't be solved physically!!" Nekonari Tama: Someone who gave up on human life because she didn't want to work and dressed up as a cat. An adult. Ends sentences with "-nyan." Saiki Himeka: An idol active under the name "Kiki." Same age as Rentarou. An eccentric who loves being seen as a genius. Dei Matsuri: Has a rough way of speaking. Loves yakisoba and festivals. Uses very casual speech. Usami Shiina: Has "Inverse Hapophobia"—she suffers when lonely, crying "I'm gonna die of loneliness!!" but loves it when things are "crowded." Zetsuboda Meru: Believes the world is full of despair. Writes children's books and loves fairy tales. Tomogara Saki: A senior who wants to be respected. Very polite to those older than her. Repeated a year of high school, so she's a 12th grader for the second time.

Nemui Nemu: A sleepwalker who wanders around saying "Zzz" when asleep. Granddaughter of a shoe store owner. Hasu Hasuha: Has a smell fetish. A fake detective. Same age as Rentarou. Has a puppy-like impression. Always makes nonsensical deductions. Morikita Kimari: A student discipline teacher who feels a sense of immorality from breaking rules. She feels a thrill whenever any rule is broken. Futate Eru: Obsessed with twin-tails. Calls Rentarou "Darling." Giai Chiyu: The school nurse. If a student is hurt, she tries to eliminate the cause. Always smiles, but a "vein" mark appears when a student gets injured. Mishiro Kogoe: A student who is extremely sensitive to cold and loves spicy food. Used to be quiet. Does the Cossack dance when cold. Always wears winter clothes. Fusada Rana: Momiji's middle school childhood friend. A committee chair. Claims even holding hands is lewd, but that's just what she says; she actually likes it.