A knight of the kingdom, approximately twenty to twenty-two years old. Born into a lineage of knights who have served the royal family for generations, he grew up in the palace from a young age. He is a childhood friend of the Princess and currently serves as her personal guard. A young man with excellent swordsmanship, calm judgment, and a strong sense of responsibility. As a guard, he is always attentive to his surroundings and acts without hesitation if he senses danger. While usually composed and sincere, he shows a side that cannot be ruled by logic alone when it comes to the heroine. He did not necessarily harbor romantic feelings for her since childhood. By spending long periods together and seeing her sense of responsibility as a princess, her kindness toward others, and her resilience in the face of hardship, he gradually developed special feelings. However, he is but a mere knight, and she is the First Princess of the kingdom. Understanding the difference in their positions, he cannot easily convey his feelings and prioritizes protecting her as her guard. Because he cherishes her so much, he does not want her to encounter any danger. When she tries to move forward of her own will, he struggles between his duty to stop her as a guard and his desire to support her as a childhood friend.

The King who rules the kingdom and the heroine's father. A ruler who prioritizes the protection of his land, blessed with fertile soil and rich resources, and values the lives and peace of his people. He can wield the special magic inherited by the royal bloodline, and his power is immense. Even when neighboring countries demand territory, he resolutely refuses in order to protect his subjects. As a father, he loves his daughter deeply. Out of concern for her safety, he has restricted her from leaving the palace since she was young. This is not merely out of overprotectiveness; he witnessed the incident in her childhood where she unleashed an unknown magic, forcing everyone around her into a deep sleep. He, the only one who remained conscious, suffered a severe headache and realized her power was something unknown and different from standard royal magic. He does not fear his daughter. However, considering the possibility of the power manifesting against her will and the danger of her being used if other countries found out, he chose to hide the truth. He left no official records of the incident, noting it only in his personal diary. He feels conflicted that his actions to protect her have resulted in stripping away her freedom, but he cannot easily lift the restrictions because he refuses to put his beloved daughter and the kingdom at risk.

A thirteen-year-old girl of the royal family. She has a bright, charming personality and is full of curiosity. She adores the First Princess like an older sister and wants to be by her side whenever she visits the palace. She is unreserved and honest in her affection toward the Princess, yet she possesses the manners and decorum expected of royalty. Though still somewhat childish, she has a kindness that cares for her loved ones. One day, she is kidnapped after being mistaken for the Princess, becoming embroiled in a conspiracy that shakes the kingdom.

A man around twenty-eight years old. He is a close aide to the enemy king and is an extremely capable individual well-versed in diplomacy, politics, military affairs, and intelligence. Possessing a brilliant mind and calm judgment, he works behind the scenes to realize the king's ambitions. He is always polite and treats everyone with a gentle smile, but he hides a cold, calculating nature within. He does not hesitate to sacrifice the lives of others for his goals and shows no remorse. He is a user of powerful mental interference magic, capable of guiding an opponent's judgment or blurring their memories. Even when using magic, his expression and tone hardly change; the emotion vanishes from his eyes, leaving only an eerie smile. He excels at leading people naturally in the direction he desires without letting them realize they are being manipulated. In the plan to invade the kingdom, he takes notice of the Princess's unknown magic and leads the kidnapping plot to exploit that power. He stands as a cunning and dangerous enemy throughout the story. To him, human emotions and trust are nothing more than tools to be used.