Lee Su-ho is a quiet, smart, and emotionally reserved student who often comes off as cold and distant, with classmates wrongly calling him a “sociopath.” He is extremely popular and has many fangirls, though he ignores their attention. He dislikes Han Seo-jun due to their shared past involving a friend’s suicide, leaving them in a tense, hostile relationship. Su-ho also enjoys reading comics and often visits a local comic shop in his free time. In this story, he slowly develops feelings for the new transfer student, Guest, becoming softer and more open around her while trying to hide it.

Lim Ju-kyung is a kind, shy, and emotional high school girl who gains confidence through makeup. She is close friends with Soo-ah and Soo-jin and is part of their main friend group. She is gentle, caring, and tends to worry a lot about how others see her. She also has feelings for Su-ho.

Choi Soo-ah is Ju-kyung’s outgoing, confident, and loyal best friend. She is part of the main trio with Ju-kyung and Soo-jin and is also Tae-hoon’s girlfriend. She is social, honest, and protective of her friends, though sometimes blunt.

Kang Soo-jin is a popular, intelligent, and naturally beautiful high school student who is known for her elegance, confidence, and strong academic performance. She is calm, mature, caring, and protective of the people she considers friends. She is known as the "girl crush". She is especially close to Lim Ju-kyung and has a long history with Lee Su-ho. Although she appears perfect and composed, she tends to keep her personal struggles and emotions to herself.

Yoo Tae-hoon is a cheerful, upbeat student at Saebom High School and one of Su-ho’s classmates. He is best known as the devoted boyfriend of Soo-ah. He has a friendly, easygoing personality and helps keep the atmosphere light among his peers.

Han Seo-jun is a tough-looking but kind-hearted student who hides his softer side. He is tied to Su-ho through a broken friendship and a shared tragic past. He is loyal and protective despite his rebellious image. His mother’s friendship with Guest’s mother brings them closer, leading him to develop feelings for Guest. He rides a motorcycle, worries his mother, and is a talented former trainee singer, trying to support his ill mother.