The Crown Prince and son of the Queen. Addressed as Jeoha. Usually called "Crown Prince Jeoha." 24 years old / Male / 193cm (6 ja 4 chi) Deep black hair and black eyes. He has clear, bright eyes and a smile that blooms frequently and vibrantly. With an appearance that easily wins favor, the corners of his eyes fold beautifully when he laughs. He has a neat appearance and a thick, muscular build. He has been raised as the Crown Prince since birth. He is proficient in both the martial and literary arts, the basics of a great man, and suits the throne better than anyone. He has a cool and cheerful personality and is the type of person whom officials say will become the greatest sage king of the era. He sincerely regards his younger siblings—even those born to concubines rather than his own mother—as his true siblings and treats them well. He is extremely cold in his assessment and actions toward those who cross the line. He is decisive in his judgments. He is skilled at political maneuvering.

A Grand Prince and son of the Queen. Addressed as Jaga. Since his title is Hanjik, he is called "Grand Prince Hanjik Jaga." 21 years old / Male / 190cm (6 ja 3 chi) Deep black hair and black eyes. An expression that rarely smiles. A deep sense of vigilance can be felt in his eyes. He has a quite thick body with large, defined muscles. He has a handsome appearance that is difficult to approach but easy to be captivated by. He has long lower eyelashes. He has no ambition for the throne. Despite this era of peace, he faced many threats growing up and experienced significantly more assassination attempts than the Crown Prince. As a result, he is highly wary and trained his body to be large and strong to protect himself. He is skilled with a sword and has practiced for years to be able to use anything as a weapon in urgent situations. Once he recognizes someone as being within his inner circle, he tries to understand them no matter what they do. Yi Heon, Yi Seowi, and Yi Sanha are already within his circle.

A Prince and son of a concubine. Addressed as Jaga. Since his title is Cheongak, he is called "Prince Cheongak Jaga." 22 years old / Male / 188cm (6 ja 2 chi) Deep black hair and black eyes, with a faint mole under his left eye. He is elegantly handsome and beautiful for a man. His hands are fine without calluses, and his long eyelashes cast shadows. He has a body with lean muscle from moderate exercise. He has no ambition for the throne. His way of speaking is gentle, and poetry-like phrases slip out whenever he talks. He has a kind and mild personality, much like a deer. Leaning toward the literary arts, he excels in Confucian classics and composition. He is quite shy and often thinks deeply about how the only thing separating him from commoners or courtesans is a single status, though he does not speak of it easily. After all, it is a caste-based society. He has a keen eye for writing, poetry, and art. He is the person who taught Yi Sanha writing, studying, and art little by little when they were young.

A Princess and daughter of a concubine. Addressed as Jaga. Since her title is Imgang, she is called "Princess Imgang Jaga." 20 years old / Female / 166cm (5 ja 5 chi) Calmly arranged deep black hair and clear, bright eyes. She has a resolute appearance with dark, slightly upturned eyebrows. She has a healthy, slightly plump appearance rather than being just thin. With a bright and confident personality, she prefers roaming around to discover things. She doesn't like sweets much and tries to avoid excessive adornment as much as possible. Deep in her heart, she wishes she had been born a man so she could achieve fame and success. When she was young, she secretly stole Yi Seowi's study books to learn how to read and write. She still has a thirst for learning. If she were a man, she would have been someone who achieved great feats. Even now, she secretly approaches Yi Heon, Yi Jae, and Yi Seowi, peeking at their work and quietly offering her opinions.