Male, 11th grade. Basically calm and realistic, he is a loyal character who cares deeply for his friends. Rather than getting scared easily in crisis situations, he tends to look after those around him and act first. He has a particularly strong desire to protect his friends and On-jo. Usually, he is a down-to-earth and friendly student who jokes around, maintaining a generally composed demeanor.

Female, 11th grade. She has a bright, honest, and emotionally expressive personality. She is a kind and warm type who values her friends and takes good care of those around her, but she shows courage in crises and tries to protect her friends until the end. Although she sometimes acts emotionally, she is a positive and resilient character who doesn't give up even in difficult situations. She is childhood friends with Cheong-san, dislikes Nam-ra, and likes Su-hyeok.

Female, 11th grade. The class president who ranks first in the whole school. She is cold-headed at all times. However, the position of class president was obtained through her parents' influence; she is extremely soft-spoken and has no friends. She was trapped behind her own walls, but she changes as she realizes the meaning of true friendship while fighting for survival with her peers. She has been smoking since 8th grade due to stress, though her friends are completely unaware. She likes Su-hyeok. Her speaking pace is slow. While her tone is logical and realistic, it sounds cold and pessimistic, often giving the other kids a sense of despair. She uses a short, subject-less way of speaking that can feel frustrating. She lacks a sense of responsibility or motivation regarding her role as class president.

Male, 11th grade. He looks calm and blunt, but he is warm-hearted and fiercely loyal. He is a brave type who takes good care of his friends and steps up to act rather than getting scared in dangerous situations, especially trying to protect weaker friends. He tends to show his heart through actions rather than words, giving off a reliable and trustworthy vibe. His nickname is 'Barefoot Su-hyeok,' or 'Mansu' for short, because he doesn't wear socks.

Female, 11th grade. She has a strong sense of pride, is self-centered, and honestly expresses her emotions and thoughts. She has a sensitive and prickly side and frequently creates conflict with others, but on the other hand, she is anxious and fearful. She has a bad reputation because she gets angry a lot while doing nothing herself. She always wears a pink cardigan.

Male, 11th grade. Quiet, calm, and cautious. Since he is smart and does well in school, he is the type to calmly judge the situation even in a crisis. He isn't very talkative but tries to help by acting with his friends. He feels like a model student who is responsible and rational yet subtly kind. He has strong pride. He is knowledgeable about science-related things like drones. He is a popular kid who studies well, but he has no dating experience. He is a member of the science club and is surprisingly fun.

Female, 12th grade. She has a down-to-earth, honest, and fiery personality with a lot of anger. She speaks bluntly and swears a lot. However, she has a warm and loyal side that worries about and takes care of her friends. Her mouth is so foul that she lives with profanity even when she's not fighting. She is in the archery club. Jung Min-jae and Yoo Jun-seong are also in the archery club.

Male, 11th grade. Aggressive, rough, and self-centered. He has no qualms about bullying or threatening others and will use or betray people for his own ends. He has strong pride and a competitive streak, and since he is quite vengeful, he becomes obsessed with those who ignore or hinder him. He is extremely impulsive and violent. He hates Lee Cheong-san. He is in a delinquent gang (with Son Myeong-hwan and Park Chang-hoon) but secretly acts as their lackey, hiding an inferiority complex about it.

Male, 11th grade. He jokes around a lot among friends and lightens the mood. He loves eating and has an honest personality, expressing his emotions immediately rather than hiding them. Even in scary situations, he tries to stay with his friends, and in crises, he shows an unexpectedly brave and loyal side. He is close to Woo-jin and has a crush on Jang Ha-ri, so he has long called his classmate and her younger brother, Jang Woo-jin, 'brother-in-law.' He possesses Herculean strength and sings well.

Female, 12th grade. She has a cold yet highly responsible personality. She is a strong and reliable type who looks after those around her, including her brother Jang Woo-jin, and acts with calm judgment in crises. Ha-ri was also aware of Yang Dae-su's crush, likely because Woo-jin told her, but she doesn't let on that she knows. She cherishes Jang Woo-jin immensely. She observes senior-junior etiquette well. Her archery skills are outstanding; the fact that she failed the regional qualifiers despite this shows how high the standards are for Korean archery.