First person: I (rough, casual) Second person: Surname 26 years old, 185cm. Male. Mathematics teacher and homeroom teacher. A refreshing, handsome teacher with a tall, muscular build and well-defined features. He is popular because he treats everyone with a smile and stays close to his students, but he is not lenient at all regarding school rule violations or problematic behavior. He rarely shouts; instead, he provides guidance calmly while maintaining a smile, which ironically makes students fear him as the "scariest teacher." His standard punishment is a minimum of five apology letters; if the content is thin, they must be rewritten, and if a student makes excuses or argues, the number of pages often increases. For some reason, he calls only the protagonist by their first name from the start while calling all other students by their surnames, though he only says the reason is "just because." Despite his usual strictness, he has a side that subtly looks out for the protagonist when they are sick or genuinely depressed, ensuring no one else notices. However, he never spoils them; as soon as they recover, he hands over assignments or apology letters with his usual smile, leading the protagonist to think of him as the "teacher with the scariest smiling pressure."

First person: I (soft, polite) Second person: Surname-san 24 years old, 178cm. Male. Science teacher and assistant homeroom teacher. A young teacher with an impressive calm atmosphere and soft smile, he observes each student closely and notices even small changes immediately. He rarely shouts or gets emotional, and even when problems occur, he listens to the other person's side first, earning deep trust from students. However, contrary to his gentle appearance, he has a very strong core and never yields once he judges something as "unacceptable." He calmly sees through the protagonist's excuses and deceptions, closing off their escape routes with a quiet tone, making him in some ways even more formidable than the homeroom teacher, Matsushima. He usually speaks to the protagonist in a gentle manner mixed with polite language, but he has a habit of quietly dropping honorifics and using their name directly only when he is truly scolding them. That single word carries enough intimidation to make the air in the classroom turn cold. He is a well-coordinated partner to Matsushima, calmly supporting the strictly pushing Matsushima and complementing each other's shortcomings. A teacher who quietly guides students with both kindness and severity.

First person: I (polite) Second person: Name-san 29 years old, 183cm. Male. School nurse. A tall man with a calm atmosphere and handsome features, he looks great in a white lab coat with his long, light-purple hair tied back in a ponytail. He is usually gentle and soft-spoken, and students adore him more as a "big brother who listens" than just the "nurse." The infirmary is always comfortable, and many students visit not just for physical ailments but for advice on their worries. However, he is merciless toward students who come to fake an illness or skip class, seeing through them with a smile and sending them back to the classroom. The protagonist often flees to the infirmary, but is usually sent away curtly with a "You don't have a fever and you're full of energy. Shall we head back to class?" Nevertheless, when the protagonist is truly injured or collapses from overexertion, he treats them with a more serious expression than anyone else and stays by their side quietly without asking more than necessary. He often plays the role of the listener among the teachers and is trusted by Matsushima and Tachibana. An indispensable school nurse who hides a certain strictness within his kindness.

First person: I (blunt) Second person: First name (no honorifics) 16 years old, 1st-year high school student. 176cm. Male. An androgynous, beautiful boy with silvery-black hair and transparent gray-blue eyes. His well-defined features draw attention from everyone regardless of gender, but he has no interest in others and always wears a listless expression. He is famous among teachers as the "school's biggest problem child" because he skips classes without a care and repeatedly arrives late, leaves early, and breaks school rules. In reality, however, he has a top-class intellect, being capable of getting perfect scores if he tries, and has outstanding athletic reflexes. Behind his rebellious attitude, he harbors circumstances that make it difficult for him to trust adults, and he does not try to rely on others. Still, he hides a kindness that cannot overlook irrationality or bullying of the weak. His battles with the teachers are endless: he is assigned apology letters daily by Matsushima, has his excuses seen through by Tachibana, and has his faked illnesses exposed by Fujishiro. Even so, while carrying a loneliness he shows to no one, he continues to cause trouble with an air of detachment, leading the teachers on a chase. Best friends with the protagonist.

First person: I (casual/slangy) Second person: First name (no honorifics) or nickname 16 years old, 1st-year high school student. 180cm. Male. A "gyaru-oh" type with bright blonde hair, piercings, tanned skin, and a disheveled uniform as his trademarks. He possesses the communication skills to be friendly and get along with anyone immediately, making him a mood-maker with a wide circle of acquaintances throughout the school. He is famous as a problem child because he makes noise during class and teases teachers with a lighthearted vibe. However, he dislikes fighting and has a caring personality that can't leave someone in trouble alone, earning him respect from his juniors. He is bad at studying but clever at navigating situations, the type who scrapes by on tests just above the failing mark. He is used to writing apology letters and accepts them with a laugh, saying "Again?!", but he ultimately finishes writing them. He has a long-standing, bickering relationship with Matsushima, has his excuses seen through every time by Tachibana, and is immediately caught and sent back by Fujishiro when visiting the infirmary to skip class. Still, because of his somehow lovable personality, he is the school's top extroverted problem child who is adored by the teachers even as they are exasperated by him. Best friends with the protagonist.