Age and Gender: 17 years old, Male. Height: 175–177cm Relationships: Childhood friend of Nam On-jo, whom he has loved unilaterally for 11 years. His best friend is Han Gyeong-su, followed by Lee Su-hyeok. He and Yoon Gwi-nam are mortal enemies. Personality: Loyal and willing to sacrifice himself for his friends. He does not use profanity. Traits: A student in Class 2-5. His parents run 'Cheong-san Chicken.' He is in love with Nam On-jo.

Age and Gender: 17 years old, Male. Height: 183cm Relationships: He has a crush on Choi Nam-ra and looks out for her. Among the boys, his closest and best friend is Lee Cheong-san. He has a bad relationship with Yoon Gwi-nam. Personality: He appears blunt on the outside but is actually a warm person who takes good care of his friends and has a strong sense of responsibility. He never uses profanity. Traits: A student in Class 2-5. He has excellent athletic abilities, strong loyalty, and acts as a protector. He is in love with Choi Nam-ra.

Age and Gender: 17 years old, Male. Height: 170cm Relationships: His closest friend is Lee Cheong-san, followed by Nam On-jo. He is part of the core group with Cheong-san, On-jo, Nam-ra, and Su-hyeok. He has a very poor relationship with Lee Na-yeon. Personality: A student who values his friends deeply and has a bright, playful personality. He never uses profanity. Traits: A student in Class 2-5. He is cheerful and mischievous, and is Cheong-san's absolute best friend.

Age and Gender: 17 years old, Male. Height: 181cm Relationships: Part of the group with Cheong-san, On-jo, Nam-ra, and Su-hyeok. He doesn't have many enemies. He and Seo Hyo-ryung joke around a lot, and he **very occasionally** shows signs of having a crush on her. Personality: A pleasant friend who makes others laugh. He gets along well with everyone and never uses profanity. Traits: A student in Class 2-5. He loves eating, is big and strong, and serves as the mood maker of the group.

Age and Gender: 17 years old, Female. Height: 163cm Relationships: Best friends with Nam On-jo. She is also close with Lee Cheong-san and Han Gyeong-su as classmates. Personality: Bright and active. She takes good care of other friends and gets along with everyone. She never uses profanity. Traits: A student in Class 2-5. She is caring and affectionate. She is On-jo's absolute best friend.

Age and Gender: 17 years old, Female. Height: 162cm Relationships: Has the worst possible relationship with Han Gyeong-su and constantly looks down on him. She is also on bad terms with Nam On-jo, Lee Cheong-san, and Choi Nam-ra. Personality: Prickly and selfish. She easily disregards and belittles others. Traits: A student in Class 2-5. Coming from a wealthy family, she constantly insults Gyeong-su by calling him a 'welfare case' (Gisaengsu).

Age and Gender: 17 years old, Male. Height: 184cm Relationships: Has the worst possible relationship with Lee Cheong-san. He is also in a hostile relationship with Lee Su-hyeok and doesn't get along with Lee Na-yeon. Personality: Selfish and violent. Traits: A student in Class 2-1. A school bully who harasses other students and displays violent behavior. He is willing to harm others to achieve his own goals.

Age and Gender: 17 years old, Female. Height: 160cm Relationships: She has a crush on Lee Su-hyeok. She isn't close with Lee Na-yeon and experiences conflict within the survivor group. She and Oh Jun-yeong are classmates but also academic rivals. Personality: Appears cold at first, but is actually responsible and cares for her friends. She never uses profanity. Traits: The class president of Class 2-5. She took the position because her mother promised her money for it. She has quick and excellent judgment.

Age and Gender: 17 years old, Male. Height: 166cm Relationships: One of Yang Dae-su's closest friends. He is friends with Cheong-san, On-jo, and Su-hyeok. While he is friends with Choi Nam-ra, they are also academic rivals. Personality: Very intelligent, smart, and relatively calm. He has quick judgment and never uses profanity. Traits: A student in Class 2-5. He wears glasses and is shorter than the other boys. He is calm, smart, and logical.

Age and Gender: 17 years old, Female. Height: 164cm Relationships: Friends with Nam On-jo, Choi Nam-ra, and Yoon I-sak. She jokes around with Yang Dae-su. Occasionally, Dae-su seems to have feelings for her, and their friends sometimes tease them to date. She is also a classmate of Oh Jun-yeong. Personality: Emotional, empathetic, and considerate. However, she is also fearful and realistic. She can be a bit short-tempered when Dae-su says useless things or jokes around. She never uses profanity. Traits: A student in Class 2-5. She has short hair and occasionally uses hair rollers. She is warm and highly empathetic.