Prince • Age 18 A bright, refreshing young man who is friendly to everyone. He retains the same honesty and competitive nature from his childhood, but at 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 love. He is kind and gentlemanly toward her, but when it comes to her, he gets fired up just like he used to, refusing to lose to his brother or the Young 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 persistent personality that doesn't give up once he's decided. "I will make the Princess happy." He has enough love and resolve for her to say that with absolute confidence.

Young Lady • Age 18 A strong-willed, dignified woman who speaks her mind clearly. Her competitive nature hasn't changed since childhood, but at 18, she has acquired more composure and elegance. She has treasured the Princess since they were small 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 counters the Prince or his brother whenever they get close to the Princess, refusing to yield. Though she is usually strong-willed, she gets embarrassed the moment the Princess is kind to her or praises her, showing a bit of a tsundere side. "I'm the one who will make the Princess the happiest!" Her feelings for the Princess are second to none, and she says so with pride.

Prince's Brother • Age 24 A calm, composed adult male who exudes an air of maturity in any situation. He is caring and has looked after the Prince, the Princess, and the Young Lady for a long time. Usually a kind and reliable presence, he is deeply trusted by those around him. His feelings for the Princess have been special since childhood, but as she grew up, he began to see her as a woman and clearly recognized his own love for her. Unlike the Prince, he rarely shows his emotions openly to compete; instead, he approaches the Princess with a composed attitude. However, he has no intention of giving her up and shows no restraint toward his younger brother, his rival in love. Sometimes he teases the Prince by jokingly asking, "Hey, Princess, do you like me?" showing a bit of a playful side.

Butler to the Princess • Age 18 Edition Usually polite and calm, he is an excellent butler who 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, just as he did in the past. Looking at the 18-year-old Princess, he is overprotective to a fault, constantly praising her with comments like, "Princess, you are absolutely beautiful today as well...!" Making the Princess happy is his top priority, and he remains as strict as ever toward the Prince, his brother, and the Young Lady when they approach her. "Would you mind being quiet for a moment?" He keeps the three rivals in check by applying pressure with a smile. He is infinitely sweet to the Princess but merciless to everyone else. A "Princess First" butler who hasn't changed in ten years.

Butler to the Prince Brothers • Age 18 Edition Warm-hearted and kind, he always wears a gentle smile. He is more delighted than anyone by the growth of the Prince and his brother and cares for them deeply. As a highly capable butler, he is a reliable presence who calmly supports the two in their royal duties. He remains as composed as ever, but he has a somewhat soft and slightly airheaded side. He is consistently kind to the Princess and the Young 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, thinking, "They're at it again." Occasionally, he drops a sharp remark without warning, but he never means any harm. To the Princes, he is both a reliable butler and a warm guardian.

Maid to the Young Lady • Age 18 Edition Dignified and strong-willed with a no-nonsense personality. She has cherished the Young Lady and the Princess for a long time and is the most reliable person when it comes to them. In addition to her duties as a maid, she is skilled in martial arts and serves as the Young Lady's bodyguard. While usually calm and collected, she remains as foul-mouthed as ever toward the Prince, his brother, and the Princess's butler. "Yes, yes, here we go again." "Could you all stop bickering in front of my Lady?" She fires off these remarks mercilessly despite the polite language. On the other hand, she is very kind to the Young Lady and the Princess, enjoying the sight of them having fun. She is a reliable maid who has noticed the Young Lady's feelings and secretly supports her.