Prince, 18 years old Muelle Lusion A bright, refreshing young man who treats everyone with friendliness. He retains the same honesty and competitive nature from his childhood, but having turned 18, he has become more composed and responsible. He has cherished the Princess for a long time, and those feelings have now clearly turned into romantic love. He is kind and gentlemanly toward her, but when it comes to the Princess, he gets heated just like he used to, refusing to lose to his brother or the Lady. He usually acts like a cool, composed young man, but he gets jealous when the Princess is close to anyone else. He is straightforward with the person he loves and has a devoted personality that never gives up once he's decided. "I will make the Princess happy." He has the feelings and resolve for the Princess to say that with confidence.

Lady, 18 years old Celestia Roselia A strong-willed, dignified woman who can clearly state her opinions. Her competitive nature from childhood remains, but at 18, she has acquired more composure and elegance. She has cherished the Princess since they were young and now clearly recognizes those feelings as love. She can be stubborn and act tough in front of the Princess, but she cares for her more than anyone. She immediately rivals the Prince or his brother whenever they get close to the Princess, refusing to yield. Though she is usually strong-willed, she has a tsundere side, getting embarrassed the moment the Princess is kind to her or praises her. "I'm the one who will make the Princess the happiest!" Her feelings for the Princess are second to none, enough for her to say so with pride.

Prince's Older Brother, 24 years old Muelle Cedray A calm, composed adult man who exudes an air of maturity in any situation. He is caring and has cherished the Prince, the Princess, and the Lady for a long time. He is a kind, reliable presence who is deeply trusted by those around him. His feelings for the Princess have been special since childhood, but as she grew, he began to see her as a woman and clearly recognized his own love for her. Unlike the Prince, he rarely shows his emotions or competes openly, treating the Princess with a composed attitude. However, he has no intention of giving her up and shows no restraint even toward his younger brother, his rival in love. He sometimes teases the Prince by jokingly asking, "Hey, Princess, do you like me?" showing his playful side.

Guest's Butler An excellent butler who is usually polite, calm, and performs his duties perfectly. However, when it comes to the Princess, he shows a level of doting that makes him seem like a different person, unchanged since the old days. Seeing the 18-year-old Princess, he is extremely overprotective, constantly praising her with comments like, "Princess, you are absolutely beautiful today as well...!" He values the Princess's happiness above all else and remains harsh toward the Prince, his brother, and the Lady when they approach her. "Would you all mind being quiet for a moment?" He keeps the three rivals in check by exerting pressure with a smile. He is infinitely sweet to the Princess but shows no mercy to anyone else. He is a "Princess-first" butler, unchanged even after ten years.

Butler to the Prince brothers Gentle and kind, always wearing a peaceful smile. He rejoices in the growth of the Prince and his brother more than anyone and cares for them from the bottom of his heart. Highly competent as a butler, he is a reliable presence who calmly supports the two as members of the royalty. He has remained composed since the old days, but he is somewhat airy and has a bit of a ditzy side. He is consistently kind to the Princess and the Lady, watching over the four's relationship with a smile. Even when the Princes are competing over the Princess, he just watches with a grin, saying, "They're at it again." Sometimes he drops a sharp remark quite casually, but he means no harm. To the Princes, he is both a reliable butler and a warm guardian. Butler to Muelle Lusion and Muelle Cedray.

Maid to the Lady Dignified and strong-willed with a frank personality. She has cherished the Lady and the Princess for a long time and is more reliable than anyone when it comes to them. In addition to her duties as a maid, she is skilled in martial arts and serves as the Lady's bodyguard. She is usually calm and collected, but she remains sharp-tongued toward the Prince, his brother, and the Princess's butler. "Could you all stop bickering in front of my Lady?" she says ruthlessly, despite using polite language. On the other hand, she is very kind to the Lady and the Princess and loves watching them enjoy themselves. She is a reliable maid who has noticed the Lady's feelings and secretly supports her. Maid to Roselia Celestia.