Name: Na Hwajin Gender: Male Age: 35 years old Height: Approx. 185cm Occupation: Field Supervisor at TRPA Background: Former Captain, Special Warfare Command Special Mission Battalion Personality: Cold, calm, strong sense of responsibility, possesses a subtle sense of humor. Features: Despite a blunt and intimidating first impression, he has a strong tendency to listen to and protect victims. As a former special forces officer, his field response skills are exceptional. He is the one who helped Lim Hanlim when she was bullied in high school.

Name: Lim Hanlim Gender: Female Age: Late 20s to early 30s Height: Approx. 168–170cm Occupation: Field Supervisor at TRPA Background: Former Sergeant First Class, Special Warfare Command (same unit as Na Hwajin) Personality: Straightforward, speaks like a drill sergeant, bold, strong sense of justice, man of action. Features: Na Hwajin's junior and right-hand person. She looks proper on the outside but is actually quite relentless, pushing through to the end if she believes she is right. Na Hwajin helped her when she was being bullied in high school.

Gender: Male Age: Late 20s to early 30s Height: Approx. 178cm Occupation: Administrative Officer at TRPA Personality: Bright and sly, but extremely intelligent. Features: The brain and information specialist of TRPA. When necessary, he goes undercover in schools. Point: He seems lighthearted but is a specialist in analyzing cases and gathering intelligence. He sometimes experiences the victim's perspective firsthand while undercover. He graduated from KAIST Computer Science two years early and is a master hacker (though he occasionally crashes things while hacking... T_T).

Gender: Male Age: Late 50s to 60s Height: Approx. 188cm Occupation: Minister of Education, Founder of TRPA, Director of TRPA, 6-term Member of the National Assembly (Happy Hope Party) Personality: Cold and cautious. Quick at political judgment. Features: The man who created TRPA. He leads Na Hwajin and Lim Hanlim, moving the organization from behind the scenes. Point: Not a fighter, but a key figure who operates TRPA through political influence and judgment. He has a very deep relationship with Na Hwajin. He had a daughter, Choi Gayoon, who was murdered by Jo Gyucheol; Na Hwajin was her fiancé.

Name: Jo Gyucheol Gender: Male Age: Estimated early 20s Height: Approx. 175cm Occupation: Former student / Juvenile detention center inmate Personality: Cunning, calculating, cold, persistent. Features: In this adaptation, he is a character who uses his brain rather than brawn, differing significantly from the original work's version. He sells drugs and plots with Hwang Gitae to destroy TRPA. He is the one who killed Choi Gayoon.

Name: Hwang Gitae Gender: Male Age: Estimated around 60 Height: Approx. 175cm Occupation: Politician Actor: Kim Jong-soo Personality: Experienced, cold, ambitious, calculating. Features: Not a physical combatant, but a man who uses political influence and power. He plays a role in shaking the very foundations of TRPA.

Age: 14 years old Height: Approx. 165cm Gender: Male Personality: Shameless, violent, and unrepentant. Features: Commits crimes by exploiting his status as a 'juvenile offender' (under the age of criminal responsibility). Crimes: Drug distribution, vehicle theft, unlicensed driving, violence, etc. Role: The central figure of the four juvenile delinquents. Key Point: He knows he won't be easily punished because of his age and abuses this fact. He hangs out with Yoon Minsu, Lee Doohyun, and Choi Woosung, acting as the leader of the group.

Gender: Female Age: High school student Height: Approx. 165cm Personality: A model student on the surface, but harbors anger and rebellion within. Features: The central figure of the Soyeon Girls' High School incident in Episode 3. Initially appears to be a troublemaker, but a different side is revealed as the background of the case is uncovered. She socially ruins teachers on Instagram. Point: Rather than a simple 'villain student,' the focus is on why she changed. Lim Hanlim intervenes through the incident involving Jung Sunyoung.

Gender: Female Age: Late 20s to 30s Height: Approx. 165–168cm Occupation: Teacher Victim

Gender: Male Age: High school student / Estimated 17–18 years old Height: Approx. 180cm Personality: Arrogant, violent, and prone to using power. Features: Son of a National Assembly member, the core leader of the school violence perpetrators at Daehan High School. Point: He acts recklessly within the school using his father's political influence and bullies other students. Kim Kwangsu and others serve as his right-hand men and enforcers.