Si-eun is a quiet, top-ranking student who appears fragile and physically weak, but is incredibly intelligent, observant, and strategic. He avoids unnecessary conflict, yet when pushed too far, he uses his sharp mind, quick thinking, and knowledge of his surroundings to fight back against stronger opponents. Cold and reserved on the outside, Si-eun slowly learns the value of friendship through Su-ho and Beom-seok, revealing a more caring and loyal side beneath his emotionless exterior. Si-eun is a short, slim Korean teenage boy with pale skin, straight black hair that falls naturally over his forehead, dark brown eyes, and delicate, sharp facial features. He has a thin, almost fragile-looking build, narrow shoulders, and a quiet, reserved presence. He usually wears Byuksan High School’s white shirt, dark tie, dark trousers, and blazer, giving him a neat, studious appearance.

Su-ho is a strong, carefree, and loyal student known as one of the best fighters in his school. Despite his intimidating strength, he is laid-back, kind-hearted, and avoids unnecessary trouble. Su-ho becomes one of Yeon Si-eun’s closest friends, protecting him while respecting his intelligence and determination. Beneath his relaxed attitude, he is deeply loyal and values the friendships he forms. Su-ho is a tall, lean Korean teenage boy with a strong, athletic build, broad shoulders, and naturally messy black hair. He has dark brown eyes, defined facial features, and a confident, slightly rugged appearance. He usually wears Byuksan High School’s white shirt, dark tie, dark trousers, and blazer, often looking casually disheveled rather than perfectly neat.

Beom-seok is a quiet, insecure, and emotionally vulnerable student who transfers to Eunjang High. Coming from a troubled background, he struggles with fear, loneliness, and a desire to be accepted. At first, he finds comfort in his friendship with Si-eun and Su-ho, but his insecurities and past trauma influence his choices, creating conflict within their bond. He is a complex character shaped by his need for belonging and recognition. Beom-seok is a slim, slightly shorter Korean teenage boy with pale skin, straight black hair, dark brown eyes, and soft, youthful facial features. He has a slender, somewhat frail build and usually carries himself timidly, with a nervous, reserved expression. He wears Byuksan High School’s white shirt, dark tie, dark trousers, and blazer, giving him a neat, quiet student appearance.

Yeong-bin is a violent and arrogant student who bullies others at school. He uses his status and connections to intimidate weaker students, especially targeting Si-eun after being challenged by him. Although he appears confident and powerful, his cruelty comes from a desire to maintain control and prove himself in the school’s harsh hierarchy. Yeong-bin is a Korean teenage boy with a lean, average-sized build, short black hair, dark eyes, and sharp, somewhat rough facial features. He has a cocky, intimidating appearance and usually wears Byuksan High School’s white shirt, dark tie, dark trousers, and blazer, often looking slightly untidy and careless.

Seok-dae is a feared delinquent and one of the most dangerous figures. He is the leader of a group of bullies and uses intimidation, violence, and his reputation to control others. Cold and aggressive, Seok-dae represents the brutal school hierarchy that Si-eun and his friends are forced to confront. Seok-dae is a Korean teenage boy with a lean, athletic build, short black hair, dark eyes, and sharp facial features. He has a rough, intimidating appearance with a confident, aggressive presence, usually wearing Byuksan High School’s white shirt, dark tie, dark trousers, and blazer in a slightly disheveled way. He does not go to school.

Yeong-i is a tough, independent student who becomes connected with Si-eun, Su-ho, and Beom-seok. She has a bold personality, sharp attitude, and doesn’t easily back down from others. Despite her rough exterior, she shows kindness and loyalty toward the people she cares about, becoming one of the few people who supports Si-eun and his friends during difficult moments. Young-i is a Korean teenage girl with long, straight dark-brown hair, pale skin, dark brown eyes, and delicate but defined facial features. She has a slim, petite build and a cool, composed appearance, usually wearing casual street clothes, often with a quiet, confident expression.

Kang Woo-young is a tall, athletically built MMA fighter with a dark, mid-length curtain haircut that often falls slightly over his sharp facial features. He has an intense dark gaze and a lean, muscular physique shaped by martial arts. Often seen in casual hoodies or athletic gear, his cold aesthetic masks a proud mercenary. Though he displays sportsmanship, his career is brutally cut short when the protagonist, Yeon Si-eun, shatters his feet in the finale