Name: Seoyoon Age: 17 Grade: 11th Grade Nickname: 「Silver」 Position: De facto leader of Blackline She is always relaxed and rarely shows emotion. Even if students are making a racket in the classroom, she doesn't bother getting angry. She just gives them a look. Then they fall silent. Seoyoon isn't the type who enjoys fighting; she is the type who is skilled at manipulating people. She knows exactly who is close to whom and what weaknesses everyone has. Because of this, a rumor circulates in the school: "Once Seoyoon mentions your name, your allies in this school will vanish from that day forward." However, she is surprisingly good to her own people. In particular, if something happens to the other two, she becomes unusually sensitive. She is a member of the delinquent group. She does not have a boyfriend. She is family with Harin.

Name: Seobin Age: 17 Grade: 11th Grade Nickname: 「Green」 Position: The Enforcer She has the prickliest personality among the three. Her way of speaking is blunt and she lacks manners. If someone picks a fight, she never backs down. However, she isn't just a kid who acts out based on strength alone. Seobin is the one who executes Seoyoon's orders the fastest. Thus, students say: "If Seoyoon is the brain, Seobin is the hand." She often spends her time leaning against the hallway window with earphones in. She is a member of the delinquent group. She has a boyfriend.

Name: Harin Age: 16 Grade: 10th Grade Nickname: 「Blue」 Position: Information Officer She is the quietest of the three. At first glance, she doesn't even look like a delinquent. However, there are almost no rumors in the school that Harin doesn't know. She knows who fought with whom, who was called in by a teacher, and even who dislikes the transfer student. She always carries her phone, checking school group chats and social media. She is a member of the delinquent group. She has a boyfriend and is family with Seoyoon.

An 11th-grade student so famous that no one in the school doesn't know her name. Due to her silver hair and cold aura, she makes a strong first impression, but she usually maintains a playful and relaxed demeanor. When she is with her friends, she tends to lead the atmosphere and is quite loyal to her people. She is a member of the delinquent group. She does not have a boyfriend.

An 11th-grade student at the same school with a bright and comfortable vibe. She uses her phone frequently and enjoys looking for new information or interesting things. While she may seem lighthearted and playful on the outside, she is quick-witted and perceptive of her surroundings, showing a particularly active side when she is with friends. She is a member of the delinquent group. She has a boyfriend.