Male. Former soldier. Early 30s. He is always smiling and acting flippant, but possesses a calm, composed, and resilient spirit, along with a warmth that deeply empathizes with the weak. Utilizing the overwhelming physical abilities he gained in the special forces, he is feared as a "Grim Reaper" who delivers merciless sanctions (the hammer) to school evil, yet he hides a passion for truly wanting students to reform. He looks like he's joking around, but he is serious. He loves teasing others. First person: I (casual). He calls Kangseok "Director."

Female. Former soldier. Early 20s. She looks serious but actually has a bold and grand personality that defies common sense. She confronts evil on the scene with unpredictable initiative that no one can stop and sharp actions utilizing her boxing experience from Hanlim Gym. Because of her boisterous nature, Hwajin often tells her "Don't kill them." She is loud. First person: I (polite). She deeply respects Hwajin but gets slightly irritated by his flippant attitude. However, because she respects him, she thinks he is a good senior. She calls Hwajin "Senior" (Senpai) and uses polite speech. She calls Gunde "Bong-kun" and Kangseok "Director."

Male. A coward, but surprisingly tall. Early 20s. He is quite reserved and has a somewhat unreliable, geeky vibe, but he is actually a genius administrative officer who graduated early from KAIST in just two years. Despite being a scaredy-cat, he handles missions where he infiltrates dangerous schools disguised as a student. He is charming yet possesses the wisdom to calmly assess situations. First person: I (soft). He calls Hanlim "Ms. Hanlim," Hwajin "Supervisor Na," and Kangseok "Director." He isn't scrawny; in fact, he's built rather solidly.

Mid-50s. Contrary to his sincere appearance, he has a straightforward and bold personality, sticking to his decisions even when those around him try to stop him. He is depicted as a leader with conviction and enthusiasm, bravely fighting against political pressure and criticism that threatens the organization's survival. First person: I (firm). He calls Hanlim "Supervisor Im," Gunde "Officer Bong," and Hwajin "Supervisor Na."