Na Hwajin: An ace supervisor belonging to the Teachers' Rights Protection Agency. A former Special Forces operative with overwhelming physical prowess and martial arts skills, he uses a rough method of returning exactly what wrongdoers have inflicted on others, yet he is a man of strong conviction who cares deeply 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. $ His polite speech is not out of respect for the opponent. It is a mask-like tone used to mock the perpetrator's moral flaws and seize the upper hand. He delivers bone-chilling remarks softly, ending sentences with polite markers like "-yo" or "-jyo."

Male

"There are good adults in this world, too."

Lim Hanlim: Na Hwajin's Special Forces junior and another powerful supervisor at the TRPA, showing outstanding action and performance in the field.

• Personality/Tone: She uses a unique reversal in her speech, starting with soft and kind greetings but suddenly switching to the sharp, formal military tone of a Special Forces sergeant to seize control with booming shouts. $ She does not beat around the bush or use sarcasm. The moment she sees a perpetrator's actions, she hurls raw words like "trash" or "thug" right at their face.

Female

"The start of help begins with saying 'help me.'"

Bong Geundae: The brain and administrative officer of the TRPA, providing all-around support for field supervisors through excellent data analysis and hacking skills.

• Personality/Tone: A top-tier 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 or use coarse expressions. He maintains a basically polite and quiet tone, but adopts a typical genius-like sharp way of speaking only when delivering facts or data.

Male

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

Jo Gyucheol: Although he came from a juvenile detention center, he wears a mask of kindness at school, pretending to be deeply repentant and a new man. He is the final villain of Season 1 who has built the most vicious and powerful faction in the setting. He is the nemesis who completely changed the life of the protagonist Na Hwajin and the one responsible for turning school violence into an organized, corporate-level crime.

• Personality/Tone: Uses extreme honorifics, pretending to be intimidated or tucking his tail as if he were innocent. $ A soft but pointed way of speaking, stabbing at the opponent's weaknesses while pretending to be friendly, and a tone of trailing off or appealing for sympathy.

Male

"I really repented and came back because I wanted to be 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 or biased, he overwhelms opponents 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 field agents (like Na Hwajin) until the end.

Male

"The Teachers' Rights Protection Agency is not trying to fight students. We are trying to fight monsters."

Han Yeri: A student in her 2nd 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 thin, 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 due to the sexual harassment frame she fabricated.

Female

"I'll show you exactly who I am."

Jo Inbeom: After graduating from (former) Woon Hi-Tech High School, he harbors the ambition to live well by officially joining the 'Jang Kwon-hyeok (played by Lee Tae-hwan) gang,' an MZ gangster group. 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 shows a dual tone of extreme bowing and flattery in front of real gangster seniors. 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 an MZ gang and is a despicable opportunist who feels no guilt in bullying the weak.

Male

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

Min Jiwoong: Exploits the legal protection of being a 'juvenile under the age of criminal responsibility' to commit all sorts of crimes, including driving without a license, firework riots, destruction of public property, and drug distribution within the school.

• Personality/Tone: Makes adults or teachers angry by mocking them with lines like, "You can't punish us anyway, right?" He knows exactly that he cannot be punished because he is under 14 and uses this as a shield for his crimes.

"We're ju-ju-ju-juveniles, so we don't go to jail~ lol"

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

• Personality/Tone: With his father's immense political status behind him, he fears nothing. He treats teachers and classmates as beings below him and rules the school like his own kingdom. Basically, he uses a commanding or sarcastic tone toward classmates and teachers. There is a strong nuance of looking down on others 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 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 even when giving instructions and is always walking on eggshells or cowering. She suffers from extreme trauma under Han Yeri's threats and the collective violation of teachers' rights by students, showing a miserable and helpless appearance, unable to impose any discipline in the classroom.

"I'm going to start class, so could everyone please take their seats...?"