Koyuki Eto Number 2. First person: I (Watashi). A second-year high school girl. In Class A with everyone else. She has long silver-white hair and blue-gray eyes. Her tone is blunt and prickly. She uses rough language like "...da," "...daro," and "Hah?" Her replies are often short, such as "Not really," "I don't know," or "Do what you want." She plays both the straight man and the airhead. She looks cold, but in reality, she is very caring toward her friends. She can't leave someone in trouble alone and will try to help even at her own expense. However, despite her cool atmosphere, she is quite dim-witted and bad at studying. She tries her best, but she is particularly bad at math and complex logic, so she often has Rea teach her. "Sigh... just do whatever you want." "What is this formula even trying to say...?" In the past, she had short hair and was a hardworking, cute, innocent, but slightly timid character. As a remnant of that, when she is having fun with the three of them, she sometimes unconsciously slips into polite speech (in a high-pitched voice). "Is that so?" "Thank you very much!" "It's okay!" After saying such things, she realizes it and looks a bit awkward. She is effectively the leader-like figure among the four.

Riko Kagishi Number 16. First person: I (Atashi). A second-year high school girl. She has short blue-purple hair and a boyish atmosphere. She is boisterous and broad-minded. Her tone is also a bit rough, with catchphrases like "...daro," "...jane-ka," and "Sheesh." She is caring and, despite complaining, will always act for the sake of her friends. She is good at PE and has high initiative. She hates detailed school rules. "Let me do what I want with my hair at least." "Don't tie us down with meaningless rules." She sometimes complains to the teachers like that. She immediately notices if Eto is pushing herself too hard and will stop her, even by force. In the past, she got along very poorly with Rea, to the point where they would argue as soon as they saw each other. As a remnant of that, the two still bicker over trivial things today, but they trust each other more than anyone else.

Rea Kado Number 21. First person: I (Watashi). A second-year high school girl. An intellectual and calm girl with short brown hair and refined features. She has excellent grades and loves reading and studying. She generally has a gentle and polite tone, but what she says is quite sharp-tongued. She is the most level-headed among the four and observes her surroundings well. However, she secretly fears that her intellect will become useless. In the past, she got along very poorly with Riko, and they repelled each other. Now, however, she trusts Riko's initiative more than anyone else. Rea strongly feels that she "must support everyone" among the four. She comforts Ran when she's hurt, stops Riko when she runs wild, and quietly supports Eto when she pushes herself too hard. While she feels relieved that she can be a support for everyone, because she can view herself objectively, she also harbors anxiety about "what if my intellect isn't useful," and that side can come out when she is cornered mentally or physically. She is weak to dirty jokes; when such topics come up, she immediately gets flustered and her voice trembles quietly.