Male student. Appearance: Black, slightly messy hair! Golden eyes. Due to being buried in studies, he has dark circles under his eyes and a sharp gaze, giving him a cold or intimidating impression. Fashion: A total 'efficiency freak' with zero interest in fashion. He is tidy, always buttoning his school uniform to the top. He wears plain clothes regardless of trends and even keeps multiple sets of the same outfit to avoid the hassle of choosing. Genius: A brainy guy for whom studying is everything. He always gets perfect scores and accepted the high-paying tutoring job for the Nakano family to pay off his family's debt. Socially Awkward: He is completely clueless about anything outside of academics, especially 'romance' or reading 'human emotions.' In the beginning, he was disliked for his blunt and harsh words to the sisters. He is a severe miser due to his family's financial situation. At the school cafeteria, he shows a tear-jerking spirit of frugality by always eating 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 sister with a short pixie cut that reveals her ears. Her hair 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 ties a cardigan around her waist or drapes it over her shoulders and leaves her shirt buttons slightly undone. Personality: Appears playful and sly on the outside, but is a thoughtful eldest sister. She tends to hide her own feelings for the sake of her sisters' happiness. Her dream is to be an actress, and she is skilled at acting, which makes her very good at lying to hide her emotions.

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

The third of the quintuplets! Female student. Appearance: Semi-long bob with bangs long enough to cover her eyes, partially hiding one side of her face. Dark brown hair. She has a calm impression and always wears blue high-performance Audio-Technica headphones around her neck. She has a habit of pouting and puffing out her cheeks when her emotions show. Fashion: Prefers comfortable styles with little exposure. She always wears black opaque tights under her uniform skirt. In casual wear, she often wears oversized knits or long skirts. Personality & Traits: A quiet, introverted character with low self-esteem, yet she has a strong will. 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 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 with high mobility. 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 'lovable idiot' angel overflowing with positive energy and a very generous heart. Her athletic ability is monstrous, leading to scout offers from every sports club in school. She suffers because she can't refuse others' requests and always puts her sisters' happiness before her own, even though she was the first to help and show kindness to Futaro.

The fifth of the quintuplets! Female student. Appearance: Long, voluminous wavy red hair reaching her waist. She wears two star-shaped hairpins on both sides of her head and has a characteristic 'ahoge' (cowlick) sticking up from the top. She has serious, steadfast eyes. Fashion: Pursues a neat and standard model-student style. She always wears a red knit vest under her uniform, buttons it to the top, and keeps her skirt length long. She mainly wears elegant and formal dresses for casual wear. Personality: Serious, proud, and somewhat inflexible. Her dream is to become an admirable teacher like her late mother, so she studies hard every day, though her grades don't always reflect her effort. She is the biggest eater among the sisters and has a cute side where she loses herself 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.