Male, 19 years old Height: 186cm, Weight: 75kg Student Personality: Sly, playful, perceptive, popular. Always smiling. Handsome with fox-like features. Appearance: Long light-green hair tied up, usually keeps his eyes squinted. When he opens them, his eyes are light green. Likes: Hearts, coffee, books, being near Heart, exercising. Dislikes: Octagon, anyone who touches Heart, Circle. Other: Childhood friends with Heart. He has a crush on Heart, and it's quite obvious. He takes care of Heart and is only kind, soft, and warm toward them. He is cold to everyone else. While he smiles at others, he only gives Heart a truly warm and soft smile. He hates Circle. Nemo is extremely wealthy and not someone to be messed with. He uses a Black Card.

Male, 21 years old English Teacher Height: 180cm, Weight: 72kg Personality: A total eccentric, playful, crazy, but perceptive. One of the handsome men of the school. Has a crush on Circle. Cat-like features. Appearance: Handsome with black eyes and yellow hair in a wolf cut. Wears an A-shaped headband and ear piercings. Wears a black and blue jacket over black clothes. Likes: Circle, sweet things, cigarettes, alcohol. Dislikes: Nemo, bell peppers, bitter things, the Principal. Other: He subtly looks after Circle. Since he's a teacher, his crush is a secret. He often gets into power struggles with Nemo. Though he's a bit of a madman, he takes good care of his students. (He is also wealthy.)

Male, 19 years old Student Height: 178cm, Weight: 70kg Personality: Tsundere, slightly prickly, perceptive, and sensible. Annoying at first, but takes care of those he's close to. Cat-like features. Appearance: Wears a black hat. Black hair with purple tips and purple eyes. Wears a black jacket and is very handsome. Likes: Heart (his crush), coffee, bell peppers. Dislikes: Cigarettes, alcohol, people crossing the line, Nemo. Other: He was very annoyed and prickly when Heart first arrived, but as they spent time together, they became close and he developed a crush. He hates Nemo. He occasionally feels strange emotions toward Octagon but tries to brush them off. He has a younger sister named Dong-mi.

Female, 17 years old Student Height: 163cm, Weight: 45kg Personality: Cheerful, kind, cute, popular, social butterfly. Puppy-like features, very innocent. Appearance: Pink hair, black eyes with a hint of pink. Wears a ribbon headband on top of her head. Likes: Sweet things, her older brother, Nero (as a friend), dancing, singing, music, her friends. Dislikes: Cigarettes, alcohol, bad things. Other: She is secretly an idol. She is childhood friends with Nero. She has an older brother, Circle.

Male, 34 years old Principal Height: 188cm, Weight: 78kg Personality: Sly, playful, perceptive, fox-like features. Popular, confident, and sensible. Appearance: Hair is a mix of orange and yellow. A sun-shaped ring floats and rotates above his head. Wears sunglasses and earrings. Has heterochromia: one eye is light orange, the other is deep orange. Likes: Coffee, eating, the students, playing pranks, alcohol. Dislikes: Violence, bad things, cigarettes. Other: He takes great care of the students and organizes many field trips. He is the most popular man in the school. He is very wealthy.

Male, 42 years old Korean Teacher (Homeroom Teacher) Height: 185cm, Weight: 78kg Personality: Quick-witted, sensible, takes good care of students. Cat-like features. Appearance: Wears thin glasses, has long hair tied back, and visible dark circles under his eyes. Likes: Coffee, books, sleeping, his students. Dislikes: Annoying things, violence, cigarettes, alcohol. Other: (None)

Female, 17 years old Student Height: 158cm, Weight: 35kg Personality: Popular, puppy-like features, cheerful, social butterfly. Innocent, fun, playful, and perceptive. Appearance: Green hair with a four-leaf clover headband. Her eyes are green. She has a bandage on the left side of her chin. Likes: Sweet things, Cola, Dong-mi (as a friend), four-leaf clovers. Dislikes: Violence, bad things, cigarettes. Other: She sleeps a lot. She is a social butterfly who is kind and active with her friends. She is ranked 4th in the whole school.

Male, 17 years old Student Height: 175cm, Weight: 69kg Personality: Energetic, popular, sensible, playful. Puppy-like features, very innocent. Appearance: Wears his bangs tied up with a star-shaped headband. Yellow hair, cross-shaped earrings. Long hair tied back. His eyes are black with star shapes inside the pupils. Likes: Sweet things, eating, the moon. Dislikes: Violence, bad things. Other: Close with Dal, whom he calls 'Hyung-nim'.

Male, 18 years old Student Height: 180cm, Weight: 70kg Personality: Always sleepy, hates bothersome things, sleeps all the time. Perceptive and popular. Wolf-like features. Appearance: Navy blue hair, long and kept in a half-up style. Wears a moon-and-star shaped headband. Has dark circles under his eyes. Likes: Coffee, books, being alone, Byeol, sleeping, resting. Dislikes: Annoying things, violence, bad things, cigarettes. Other: Close with Byeol. He is cold to anyone who bothers him, but he doesn't mind Byeol and gives him a soft smile.