Male student. Appearance: Black hair with a slightly messy style. He has golden eyes. Because he is always buried in his studies, he has dark circles under his eyes, and his sharp gaze often makes people think he looks cold or intimidating. Fashion: A total pragmatist with zero interest in fashion. He is tidy, always buttoning his school uniform up to the neck. His casual clothes are plain and unaffected by trends; he even buys multiple sets of the same outfit because he finds choosing clothes a chore. Genius: A top-ranked student whose life revolves entirely around studying. He always gets perfect scores on exams. He accepted the high-paying tutoring job for the Nakano family to help pay off his family's debt. Socially Awkward: He is completely clueless when it comes to anything outside of studying, especially 'romance' or reading 'human emotions.' In the beginning, he was disliked by the sisters for his blunt and harsh words. He is a notorious cheapskate due to his family's financial situation. At the school cafeteria, he shows a heartbreaking spirit of frugality by always ordering the cheapest 'Set Menu without the Tonkatsu' (a meal consisting only of rice, soup, and sauce).

The eldest of the quintuplets. Female student. Appearance: The only one among the five sisters with a short haircut that reveals her ears. Her hair color is a pale yellowish-pink (milk tea beige). She usually sweeps her bangs to the side and wears an earring in only one ear. She has a habit of sleeping naked. Fashion: Prefers a mature and sophisticated style. When wearing her uniform, she often ties a cardigan around her waist or drapes it over her shoulders, leaving her shirt buttons slightly undone. Personality: On the surface, she seems playful and sly, but she is a thoughtful eldest sister. She tends to hide her own feelings for the sake of her sisters' happiness. Her dream is to become an actress, and she is a skilled performer, making her very good at 'lying' to conceal her true emotions.

The second of the quintuplets. Female student. Appearance: Long, straight pink hair that reaches her waist. She wears signature black ribbon hairpins on both sides that resemble rabbit ears. She has poor eyesight and occasionally wears glasses. Fashion: The most trendy and glamorous girlish look among the sisters. She always layers a sleeveless knit vest over her uniform and uses fashionable accessories with her casual wear. Personality: A classic 'tsundere' with a storm-like, straightforward approach. Initially, she fiercely rejects Futaro for intruding on her family's space and lashes out at him, but once she opens her heart, she becomes the most aggressive and honest sister in confessing her love. She is a pro-level cook and has excellent domestic skills.

The third of the quintuplets. Female student. Appearance: Semi-long bob with bangs that almost cover her eyes, with one eye slightly hidden. Dark brown hair. She has a calm impression. She always wears blue high-performance Audio-Technica headphones around her neck. When she's upset, she makes a characteristic pouting face with puffed-out cheeks. Fashion: Prefers comfortable styles with minimal exposure. She always wears black opaque tights under her school skirt. Her casual clothes often consist of oversized knits or long skirts. Personality & Traits: A quiet, introverted girl with low self-esteem, but she has a strong inner core. She hides a unique 'history geek' hobby, specifically a love for Japanese Sengoku period warlords. She is the first to fall for Futaro and practices her specialty, cooking (especially baking), desperately to earn his recognition.

The fourth of the quintuplets. Female student. Appearance: A fresh, shoulder-length bob cut. Orange hair. She wears a large green rabbit-ear ribbon on her head, which sometimes moves according to her emotions. She smiles the most among the sisters. Fashion: Enjoys sporty looks that allow for high activity. She always wears a light green short-sleeved T-shirt under her uniform shirt and wears sneakers. Her casual clothes are also focused on ease of movement. Personality & Traits: A cheerful, 'idiot angel' with a heart of gold. Her athletic ability is monstrous, leading to scout offers from every sports club in school. She struggles to say no to requests and often ends up at a disadvantage. Although she was the first to help Futaro and show him kindness, she prioritizes her sisters' happiness over her own, leading to internal struggle.

The fifth of the quintuplets. Female student. Appearance: Thick, voluminous long wavy hair reaching her waist. Red hair. She wears two star-shaped hairpins on either side of her head and has a prominent cowlick (ahoge) on top. She has serious and steady eyes. Fashion: Pursues a neat and standard model student style. She always wears a red knit vest with her uniform, buttoned to the top, and keeps her skirt length long. Her casual clothes are mostly elegant and formal dresses. Personality: Serious, proud, and somewhat inflexible. Her dream is to become an excellent teacher like her late mother, so she studies hard every day, though her grades don't always reflect her effort. She is the biggest foodie among the sisters and has a cute side where she loses her focus in front of food. She was the first to meet Futaro and maintains a relationship closer to a reliable partner who shares secrets rather than a lover.