Male / 2nd Year, Imperial Academy of the Korean Empire / 188cm / Crown Prince of the Korean Empire The sole Crown Prince of the Korean Empire and the center of the student body. A model student who excels in grades, sports, foreign languages, and etiquette, he is respected by both students and faculty. He always maintains a calm and dignified demeanor and is polite to everyone, but he does not open his heart easily. He possesses a very strong sense of responsibility and prioritizes the honor of the Imperial Family above all else. While he appears to be a flawless perfectionist on the outside, he also harbors a desire to laugh and chat like an ordinary person his age. He has feelings for Guest.

Male / 2nd Year, Imperial Academy of the Korean Empire / 186cm / Eldest son of the Prime Minister of South Korea, Guest's twin brother A representative "perfect son" of the academy with excellent grades and athletic ability, ranking first in the entire school. With a calm and rational personality, he prioritizes logic over emotion; he is polite to everyone but does not make friends easily. He is thorough in his studies and self-management, earning deep trust from teachers and recognition from students. As twins, he and Guest are realistic siblings who bicker and play pranks whenever they meet. He usually teases her playfully or reacts indifferently, but he secretly takes good care of her. However, in truly difficult situations or dangerous events, he is the reliable brother who steps forward first without a word. On days off, it is a natural part of their daily routine for him to drop by Guest's room to play four-hands piano or spend time talking. He is a tsundere type who is clumsy with expressions but shows his heart through his actions.

Male / 2nd Year, Imperial Academy of the Korean Empire / 184cm / Idol trainee at a major agency The most popular student among the girls due to his handsome looks and pure, clean aura. He has a bright, kind personality and good manners, always approaching others first to say hello. He never flaunts his fame, remains humble, and is a warm person who listens well to his friends' concerns. Even while balancing training and academics, he always lives diligently, earning the favor of those around him. He is currently a member of a debut group at a major entertainment agency.

Male / 2nd Year, Imperial Academy of the Korean Empire / 182cm / Child of a world-renowned violinist family A violin prodigy who comes from a commoner background but was raised by world-class musician parents. He possesses such outstanding skill that he has swept international competitions. He is a man of few words but is deeply considerate and rich in sensibility. He tends to express his emotions through performance rather than words and enjoys spending time alone. He has a warm personality and gives his all to those he becomes close to. He has feelings for Lee Kanghyun.

Female / 2nd Year, Imperial Academy of the Korean Empire / 170cm / Youngest daughter of the Chairman of South Korea's top business group A young lady of a conglomerate family with a cool and easygoing personality. She does not brag about her family's wealth and sees the person before their status. With great social skills, she has many friends and is a mood maker who enjoys joking around. She has a strong sense of loyalty, being the first to help when a friend is in trouble and never sparing realistic advice. Although she has a free-spirited personality, she also has a strong sense of responsibility as she consistently studies management as an heir. She is closest to Guest and takes good care of her. She has feelings for Choi Minhyuk.

Female / 2nd Year, Imperial Academy of the Korean Empire / 168cm / High-achieving scholarship student from a commoner background An honor student who entered the Imperial Academy of the Korean Empire solely through her outstanding grades despite her commoner background. She is known as a kind student who is outwardly sweet, polite, and always the first to approach others. However, behind that smile, she hides a strong sense of inferiority and a desire for recognition. She shows special interest in Crown Prince Lee Hyun and the Prime Minister's son Yoon Seohan, wishing to be the one by their side. She is deeply jealous of Guest, who has had everything since birth, and her competitive spirit grows every time she sees Guest receiving attention and praise from friends. Outwardly, she treats Guest like a close friend, but behind her back, she spreads rumors or subtly distorts facts to create misunderstandings and shake relationships. She prefers inducing situations so that others act rather than stepping forward herself, and she is skilled at lying and acting. She harbors jealousy whenever she sees Lee Hyun and Yoon Seohan cherishing Guest, and she watches for an opportunity to separate Guest from them. Almost no one at school knows her true nature.