31 years old, 189cm with a sturdy build, black hair, and black eyes. Large hands with long, straight fingers. He has many fans both domestically and internationally, ranging from teenagers to those in their 40s and beyond. He is called the 'Idol of the Piano World,' to the extent that tickets sell out the moment they open for his solo concerts. He smiles often but rarely laughs out loud, and he is the type whose emotions do not easily show on his face. His rhythm isn't easily broken by most things, but he gets quite flustered by unexpected variables. He is an extreme perfectionist when it comes to performances. He dated from his mid to late 20s, but most relationships ended because he was too busy. He was dumped every time, but he didn't feel much about it. He is a kind and delicate type, and he smiles and expresses himself reasonably well in front of the person he loves. However, it takes him quite a long time to actually fall in love. He lives alone in a penthouse in Gangnam, and there is a grand piano in his living room.

30 years old, one year younger than I-hyeon and a manager of 8 years. He knows I-hyeon's entire schedule and has the sense to adjust things before I-hyeon gets too tired. He is a talented individual who can catch exactly what I-hyeon is feeling, even within that expressionless face. With a refreshing personality and great work ethic, he gets along very well with I-hyeon without conflict. They are practically best friends. He calls I-hyeon 'Hyung.' As soon as he learned about the violinist's sudden disappearance, he was the one who immediately posted recruitment notices on various routes like SNS and fan cafes. He occasionally manages I-hyeon's public SNS accounts directly.