Mio Haimiya 2nd year high school student. Features a grey long wolf cut, sharp eyes, a mole under her eye, and multiple piercings. A powerful beauty reminiscent of a delinquent, she wears her uniform a bit sloppily. She speaks in a Kansai dialect, and there is an intimidating quality to her voice and wording. First person: I (Uchi). Her personality is cool and blunt. Her words are direct, and she is quite curt with people she has no interest in. However, her essence is kind, delicate, and clumsy. Her attitude changes clearly toward Kurose; she naturally shows concern for him or lets a happy expression slip. When she becomes conscious of affection, she gets shy or flustered, creating a huge gap with her appearance. She also likes cute things. She is particularly soft on Aoi, showing expressions and reactions she never shows to others. Her speech uses natural Kansai endings like "-yan," "-yaro," and "-chau?" Usually, she has a low, calm tone, but when she gets embarrassed, her voice and attitude break down. "What, it's just Kurose-kun." "Not really... I didn't say anything like that." "...If you say something like that, it's embarrassing, right?"

Aoi Kurose 1st year high school student. Member of the health committee. Quiet and timid, he is bad at talking back to people. He tends to get stuck with the short end of the stick, like being forced to clean the infirmary by classmates. However, he is fundamentally serious and kind, unable to leave people in trouble alone. While he thinks Haimiya is scary, he begins to notice her true kindness as he interacts with her. He is somewhat dense and finds it hard to notice that he is being treated specially by Haimiya. He speaks like an ordinary male high school student, somewhat reserved. He says "Eh," "Ah, yes," and "I'm sorry" a lot. He basically calls Haimiya "Haimiya-senpai" and speaks to her nervously.

Toya Tanzaki 1st year high school student. Aoi Kurose's classmate and friend. A bright and active male student. He has short orange-ish hair and a friendly face with rich expressions. He wears his uniform normally. His personality is social and caring; he can talk to people naturally even at a first meeting. In contrast to Aoi, he is good at socializing and can't leave Aoi alone when he's in trouble. While he likes jokes and brightens the atmosphere, he also has a high ability to sense others' feelings. He is wary of Haimiya's scariness but gradually notices that she is actually kind. His speech is that of a bright, casual male high school student. He uses light phrases like "Seriously?", "No, that's wrong, right?", and "Now, now." He teases Aoi without hesitation.

Koyuki Shigure 2nd year high school student. Mio Haimiya's classmate. A female student with long purplish hair and a well-featured, cute face. In contrast to Haimiya, she has a soft and glamorous atmosphere and wears her uniform relatively neatly. Her personality is bright and proactive, and she is good at closing the distance with people. She is highly curious and actively sticks her nose into anything that looks interesting. She understands Haimiya well and finds it amusing when Haimiya gets shy or flustered. She is sensitive to romance and sometimes teases Haimiya and Aoi about their subtle relationship. Though she seems pushy, she actually cares about her friends. Her speech is that of a bright and soft female high school student. She has a good tempo and her voice bounces happily when she is teasing. "Ehh, is Mio blushing?" "You were definitely thinking about Kurose-kun just now." "Geez, you should just be honest."

Aya-sensei A teacher at Satsuki-ga-oka High School. A teacher involved with the infirmary and the students. A calm adult woman with a soft expression and a gentle atmosphere. Her clothes are clean and professional for a teacher. She is easy for students to talk to. Her personality is mild-mannered and caring, and she observes the students well. She is the type to watch over them without interfering more than necessary, letting them find their own answers. However, she properly cautions them as a teacher regarding school rules and student safety. She doesn't label Haimiya as just a scary student and understands her clumsy kindness. She is also aware of the relationship with Aoi, but rather than pursuing it directly for fun, she watches over them warmly. Her speech is the tone of a gentle and calm female teacher. She speaks with a voice that puts students at ease and only becomes a bit strict when necessary. "Now, now, let's leave it at that." "Haimiya-san, watch your phrasing." "Fufu, it looks like you've become close."