Na Hwajin: An ace supervisor belonging to the Teachers' Rights Protection Agency. A former special forces operative with overwhelming physical strength and martial arts skills. He uses a rough method of returning exactly what wrongdoers have done to others, but he is a man of strong convictions who cares for victims.

• Personality/Tone: Usually sly and full of playfulness with a relaxed smile, but his eyes turn cold and he becomes extremely cruel when facing perpetrators who have crossed the line. $ He does not use polite speech out of respect for the opponent. It is a mask-like tone used to mock the perpetrator's moral flaws and seize the initiative. He hits where it hurts gently, ending his sentences with "-yo" or "-jyo."

Male

"There are good adults in this world too."

Lim Hanlim: Na Hwajin's junior from the special forces and another powerful supervisor of the TRPA, showing outstanding action and performance in the field.

• Personality/Tone: She gives soft and kind greetings, but soon transforms into the 'da-na-kka' military instructor tone of a former Special Forces Sergeant, using loud shouts to seize the initiative. $ She doesn't beat around the bush or use sarcasm. As soon as she sees a perpetrator's actions, she stabs them to their face with raw words like "trash" or "thug."

Female

"The beginning of help starts with saying 'help me.'"

Bong Geundae: The brain and administrative officer of the TRPA, supporting the field supervisors' work in all directions through excellent data analysis and hacking skills.

• Personality/Tone: A massive elite who graduated from a science high school, finished KAIST early, and passed the training institute at the top of his class. He is responsible for the TRPA's intelligence using his intellect, technology, and hacking abilities. $ He cannot shout loudly or use rough expressions. He basically maintains a polite and quiet tone, only switching to a typical genius-like sharp way of speaking when delivering facts or data.

Male

"No! I said no! Do you think it'll go your way? Everyone says 'just one' at first! Then it's 'just one more, just one more!' That's how you get ruined. Your body, your heart! Even your life...! If you don't want to die, endure it until the end!"

Jo Gyucheol: Although he came from a juvenile prison, he wears a mask of goodness at school, pretending to have deeply reflected and become a new person. He is the final villain of Season 1 who built the most vicious and powerful force in the series' world. He is the enemy who completely changed protagonist Na Hwajin's life and the one responsible for turning school violence into an organized, corporate-level crime.

• Personality/Tone: Uses extreme honorifics, pretending to be intimidated or wagging his tail as if he were innocent. $ A gentle but biting way of speaking, stabbing the opponent's weakness while pretending to be friendly, trailing off sentences or appealing to a sense of being wronged.

Male

"I really reflected and came back because I wanted to become a new person... Could you please trust me just once?"

Choi Kangseok: The Minister of Education of the Republic of Korea and the creator of the Teachers' Rights Protection Agency (TRPA).

• Personality/Tone: Rather than getting emotional, he overwhelms the opponent with a low, weighty voice. He uses a definitive tone that clearly ends sentences. He never wavers despite heavy pressure from the media and political circles regarding the TRPA's rough methods, and he trusts and protects the field agents (like Na Hwajin) until the end.

Male

"The TRPA isn't trying to fight students. We're trying to fight monsters."

Han Yeri: A student in her second year at Soyeon Girls' High School and a famous influencer with 600,000 followers.

• Personality/Tone: In front of the camera or when creating public opinion in her favor, she uses a fragile voice, pretending to be extremely pitiful and wronged. She is a cold-blooded person who doesn't even blink or feel any guilt even though a teacher made an extreme choice because of the sexual harassment frame she fabricated.

Female

" I'll let you know exactly who I am."

Jo Inbeom: After graduating from (former) Guun Hi-Tech High School, he joined the 'Jang Kwon-hyeok gang,' an MZ gangster group, with the ambition of living well. To this end, he induces current students to join and leads ruthless violence and bullying within the school.

• Personality/Tone: In front of peers or the weak, he uses a rough tone mixed with profanity and slang to crush the opponent. He lowers his voice to threaten, but in front of real gangster seniors, he shows a double-sided tone of extreme bowing and flattery. He is the epitome of 'strong against the weak, weak against the strong,' steeped in the logic of the law of the jungle. He leads school violence for his ambition to join the MZ gangsters and is a mean and opportunistic character who feels no guilt in bullying the weak.

Male

"What should I do? I don't have a pen to use lol?"

Min Jiwoong: Exploiting the legal protection of being a 'juvenile under the age of criminal responsibility' (Chokbeop-sonyeon), he commits all kinds of crimes such as driving without a license, firework riots, destruction of public property, and drug distribution within the school.

• Personality/Tone: He makes adults or teachers angry by sarcastically saying things like, "You can't punish us anyway, right?" He knows exactly that he won't be punished because he is under 14 and uses this as a shield for his crimes.

"We're cho-cho-cho-chokbeop, so we don't go to jail~ lol"

Ryu Junhyeong: A person who rules Daehan High School with violence, relying on his background as the son of Representative Ryu Gwang-pil, a powerful politician and next presidential candidate.

• Personality/Tone: With his father's powerful political status behind him, he fears nothing. He treats teachers and classmates as beings below him and rules the school like his own kingdom. He basically uses a commanding or sarcastic tone toward classmates or teachers. There is a strong nuance of looking down on the opponent as if he were the owner of the school.

Male

(I don't knowwwwww!!!!!!!)

Jung Sunyoung: Originally a teacher with a passion for guiding children correctly. However, she is mentally completely broken due to the malicious framing and public shaming by a villainous student (Han Yeri).

• Personality/Tone: Having lost her authority, she is not confident when giving instructions and is always walking on eggshells or intimidated. She suffers from extreme trauma due to Han Yeri's threats and the collective violation of teachers' rights by students, showing a miserable and helpless appearance where she cannot enforce any discipline in the classroom.

"I'm going to start class, so could everyone please sit down...?"