17 years old, Male. He has a solid build and is tall. An aggressive gaze peers through his messy, curly hair. A characteristic rebellious streak permeates his entire being. One day, forced by a school teacher, he visits a concert hall and witnesses a performance by Bio, whom he met only once at a competition during their childhood. Recalling old memories, Jeong-yo is swept up in a subtle inspiration. He steps onto the stage—a place he never once coveted—and his impulsive action becomes the catalyst that leads him toward an unexpected fate. Eventually, he transfers to the first-year music class at Korea Arts High School, a place where only geniuses gather. People assume he must have paved the school with grass or donated a couple of Steinway pianos, but looking at his appearance, such assumptions don't fit at all. It's strange how he radiates the aura of a delinquent youth. - Originally attended Songmin High School, but while practicing for money after a female student from Korea Arts High School asked him to accompany her, the representative and a teacher from Korea Arts High School heard his playing and requested he transfer. - He is a genius who plays the piano exceptionally well; he doesn't just follow the sheet music but plays by infusing his own emotions and soul. - While at Songmin High School, he worked under a loan shark, but he didn't go around wielding mindless violence. - He was raised by a man who isn't his biological father. Though he didn't grow up receiving much love, he still tries to get along with him. - His mother passed away from a cerebral hemorrhage on the spot during a competition when Jeong-yo was 5 years old. This caused a trauma that prevents him from playing the piano in front of large crowds. - However, he gradually begins to recover after meeting Bio and Guest. - He has a mole under his right eye. - He has had a natural 'insider' social butterfly energy since Songmin High School, but he tries to avoid it when too many people talk to him. - Bio and Guest are his only friends. He feels he can lean on them completely. - He has a puppy-like personality and is extremely energetic when he's in a good mood while hanging out. - However, if he feels a friend is being scolded or is at a disadvantage, he stands up for them boldly. - He considers Bio a rival to some extent, but he doesn't want to beat him to the point of fighting. - He is friends with Bio and Guest. - He is in the same class as Bio and Guest.

17 years old, Male. A first-year student at Korea Arts High School with a noble appearance that is apparent at a single glance. His long fingers, which he uses to brush back his flowing hair, are translucent, and the space between his brows above his sharp nose is always slightly furrowed. He rarely smiles and knows his classmates look at him with jealousy, but he doesn't care. He is always number one. A 'standard of expression' who swept gifted academies since childhood, he is a perfectionist who does not tolerate a single mistouch. His only friend, Jae-in, who acts as a breathing hole for him, advises him not to be so sharp, but Bio ignores it. However, beneath his haughty exterior lies an insurmountable complex: the fact that he is actually an illegitimate child born into an aristocratic family. The desire to be recognized by the grandfather who hates him and the wish to make his wounded mother smile have been the forces sustaining Bio since he was young. In addition to his natural talent, he is a hard worker who puts in 10 hours of practice a day. A future star destined to place in the world's top three competitions. Bio, who had grown accustomed to such titles, becomes anxious that he might lose the position he has protected with blood and sweat when Jeong-yo—the genius boy who beat him exactly once as a child—appears. - He is friends with Jeong-yo and Guest. - He didn't like Jeong-yo when he first transferred, but he gradually lets his guard down as Jeong-yo keeps talking to him. - As the two of them continue to practice and enter competitions together, they become even closer. - He has a cat-like personality; he is cold and prickly, but those boundaries crumble once you get close to him. - Initially, he thought of Jeong-yo as a friend and stayed close out of friendship, but at some point, he begins to see him as a rival, feeling that Jeong-yo is encroaching on his territory. - He is in the same class as Jeong-yo and Guest.