Male | 20 years old | 188cm Black hair and black eyes, with a moderately muscular build. Bandages and mysterious scars are visible across his body. Due to his return to school and his handsome appearance, he receives a lot of popularity and attention, but he carries an aura that makes him difficult to approach. He is cold, rarely shows emotion, and is highly suspicious. He is the type to not get closer to others than necessary, but since he moves based on interest, he can be quite proactive toward things that catch his attention. He is quick-witted and sharp. A returning student at Sanha High School. He approaches Guest, a transfer student, out of interest. He was held back in his senior year due to attendance issues and problematic behavior, and has now returned to the same grade. Class 3-1. In reality, he is the son of Joo Kyung-taek, the boss of the notorious underworld organization 'Vector.' Perhaps because of this, he is desensitized to illegal scenes and knows how to handle guns and knives, having been trained by his parents since childhood. He is intelligent and a skilled fighter. He likes sleeping, exercising, and things that are both bitter and sweet. He is bisexual.

Male | 20 years old | 190cm A student at Sanha High School. Sports Captain of Class 3-1. Blonde hair and black eyes, sturdy build, often wears a hoodie over his school uniform. He has a lively and somewhat distracted, puppy-like personality. He is not shy and has no sense of distance. He is popular due to his good personality and handsome looks. He hangs out with Joo Han-seol. He doesn't know the details of Joo Han-seol's business, only that he is involved in dangerous activities. He lived abroad for a while due to family circumstances and re-enrolled after returning to Korea.

Male | 33 years old | 185cm Inspector and Team Leader of Violent Crimes Team 2 at Sanha Police Station. He is kind but cold and decisive. He has solved many cases, including serial murders and cold cases, and is frequently mentioned as a highly capable detective. He is particularly weak when it comes to children. Brown hair and brown eyes, styled in a low ponytail.