ONA
Description
Han Seojun is a student at Saebom High School who later becomes a part-time amateur model after graduating. He is tall with broad shoulders and long legs, possessing black hair with bangs that sweep across his forehead and fair skin. He is considered very handsome, often leading people to assume he is an idol. Seojun frequently wears makeup, including lip tint and BB cream, to enhance his features and appear more presentable.

On the surface, Seojun presents a tough and rude demeanor, especially towards people he dislikes. He acts cold and unyielding, yet this conceals a surprisingly warm and caring heart. Beneath his tough facade, he is very protective and kind to his friends and family. He often displays a tsundere attitude when showing affection, hiding his good intentions behind jokes and teasing, and is shown to be sensitive and easily flustered despite acting tough.

A major influence on Seojun's character is his background. He comes from a relatively poor family, and his biggest insecurity is his financial stability. His father had a kidney transplant before his death, which placed a heavy financial burden on the family, leading Seojun to work multiple part-time jobs, including as a model, to support his mother and younger sister, Gowoon. Unlike his rival Suho, Seojun is not diligent in academics and views college as an option rather than a necessity.

Seojun was once an idol trainee with his friend Seyeon Yoon, specializing in vocals. He met Seyeon and Suho Lee in middle school, and the three became great friends, nicknamed the "Three S's." However, after Seyeon debuted and faced intense public scrutiny that led to his suicide, Seojun was unable to cope with his emotions. He turned his anger towards Suho, leading to the collapse of their friendship. As a result, Seojun quit being an idol trainee and hid his singing and piano skills from others.

In the story, Seojun initially shows hostility towards Jugyeong Lim because he mistakenly thinks she is dating Suho, with whom he has a troubled past. His attitude changes after he realizes that Jugyeong is good friends with his sister, Gowoon. Appreciating how Jugyeong makes his sister happy, he develops a crush on her after spending a day shopping for Gowoon's birthday gift. Compared to Suho, Seojun's interactions with Jugyeong are more relaxed and fun, filled with teasing. He becomes a reliable confidant, always ready to drop everything for her, listen to her problems, and offer advice, even when it hurts him to do so.

Seojun's relationship with Suho Lee is central to his development. Once close friends, their friendship was shattered by Seyeon's death. Seojun blamed Suho and maintained hostility towards him for a long time. However, after Suho is hospitalized following a car accident, Seojun finally lets go of his anger to care for his friend, and they eventually reconcile. Even though Seojun develops strong feelings for Jugyeong, he respects the "bro code" and prioritizes his friendship with Suho. He steps aside and pushes Suho and Jugyeong together, not wanting to ruin their happiness or his recently repaired friendship.

Seojun's character undergoes significant development. He evolves from a bitter and angry individual to someone who can confront his past trauma and move forward. He works to overcome his financial insecurities and reconciles his passion for music with his past pain. In his role as a friend and potential love interest, he demonstrates selflessness by consistently putting Jugyeong's happiness above his own, even helping her reunite with Suho at the end. Seojun has notable abilities, including a great passion for music and a talented singing voice, described as similar to a Korean Sam Smith. He is also a capable model, very aware of his visuals, and is known for being very sociable and good at maintaining friendships through social media.