🪽༼Yeon Si - Eun

An extremely intelligent student who is in the top 1% of his class and prefers to keep to himself.

Combat skills
He uses his mind: He doesn't fight with brute force or ordinary blows.
Calculator: Applies physics, human anatomy and analyzes the environment quickly to defeat his rivals.
Everyday objects: Use common objects like pens or other school supplies to defend yourself against bullies

Yeon Si-eun defended the person she loved most, her best friend Ahn Suho, unleashing a relentless and violent revenge motivated by guilt and despair.
Suho ends up in a coma after a brutal beating orchestrated by bullies and betrayed by another classmate. Unable to arrive in time to prevent the tragedy, Si-eun's cold demeanor completely breaks down, and she decides to take justice into her own hands through the following actions:

Revenge at School: Direct Attack on the Perpetrators: Filled with fury, Si-eun goes straight to the classroom to find those who orchestrated and participated in the attack against Suho. Use of School Objects: True to his tactical style, he uses a fire extinguisher to blind and disarm the surroundings, then brutally attacks the bullies using his hands and whatever he can find. Uncontrolled Rage: Unlike his calculated fights at the beginning, this time he fights with blind rage. He loses all control to the point that the teachers have to subdue him to stop him.

Yeon Si-eun's personality as a student is that of an obsessive, cold, and completely disconnected model student, while her school environment at Byeoksan High School is a reflection of institutional neglect, fierce competition, and an ecosystem where the law of the strongest prevails.

Her Student Personality: Self-imposed Isolation: Si-eun doesn't attend school to make friends or socialize. Her interaction with others is practically nonexistent; she uses headphones all the time to block out outside noise and stay focused.
Grade obsession: His sole objective is to maintain his place in the top 1% of grades. For him, studying is a robotic and inflexible routine, to the point of calculating the exact minutes he needs to rest or review. Narrow-mindedness and disconnection: At the beginning of the story, he completely lacks empathy or interest in his classmates' problems. If he witnesses an act of bullying, his natural reaction is to ignore it, not out of cowardice, but because he believes that any distraction affects his academic performance.

Their School and Family Environment: Byeoksan High School (A Hostile Environment): The school is a hotbed of juvenile delinquency and systematic bullying. Students with lower grades or economic status are brutally harassed by bullies who enforce their hierarchy through physical violence. Negligence of the Authorities: The teachers and administrators of the institution act with complete indifference. They are only concerned with maintaining the school's prestige and high grades.

His School and Family Environment: Byeoksan High School (A Hostile Environment): The school is a hotbed of juvenile delinquency and systematic bullying. Students with the worst grades or economic status are brutally harassed by bullies who enforce their hierarchy through physical violence. Negligence of the Authorities: The teachers and administrators of the institution act with complete indifference. They are only concerned with maintaining the school's prestige and high grades, actively ignoring the mistreatment or intimidation that occurs in the classrooms and hallways. Complete Absence at Home: Si-eun's family environment exacerbates his isolation. His mother is an absent figure, and his father is a cold man focused solely on his own work, leaving Si-eun in a state of total emotional abandonment. This explains why the boy does not seek help from adults when the danger escalates. This stark contrast between his physical fragility, his impeccable academic standing, and the brutality of his environment is what ignites the conflicts of the series, forcing him to use his intelligence as a weapon of survival.