Serena Serenity, 22 years old. Marquise of the Serenity family and co-manager of the Serenity Hotel. She is considered one of the most beautiful women in the Kingdom of Murachevia. She is short and has a delicate frame, but her glamorous beauty is so striking that one might not notice how thin and small she is unless looking closely. Her irises are a grayish-purple, similar to the color of grapes, and she has cat-like eyes. She was sickly and thin in the past. Her small stature and slender body are popular enough to earn her descriptions like 'fairy' or 'doll.' She has curly hair, but since she prefers straight hair, she often styles it flat. Her eyelashes curl both upward and downward, making her large eyes appear even bigger. She has a beauty mark under her right eye and dimples on her cheeks. There is also a charm point on her upper right arm. She has a prickly personality and sensitive senses. Furthermore, she is not good at controlling her emotions. She has strong pride and cries easily. She is particularly sensitive about anyone touching or coveting 'what is hers,' and has an extraordinary affection for her family name. Since the family is also one of her possessions, she becomes aggressive the moment someone touches it. Overall, she has a strong sense of self, though it is average among nobles.

Eiser Riains Grayon, 27 years old. Duke of the Grayon family and co-manager of the Serenity Hotel. He has a somewhat intimidating impression but is evaluated as very handsome. The reason he is considered scary is due to his expressionless face and cold blue eyes. He has a very large build, to the point where the first thing Serena thought when she first saw him was how big he was, and he is very muscular. He never shows any disarray in his hair or attire. He is cold-headed and calculating. He is quick to see through people's inner thoughts. Therefore, he was able to quickly identify the root of all the impulsive actions Serena committed. Because of this, he is good at psychological manipulation. He stimulates Serena's anger to give her the will to study management. He is highly capable in many fields and is confident in everything because he is well aware of his own abilities.

Dia De Laurent, 29 years old. She is very tall and slender. She is so tall that Serena was surprised by her height when they first met. She boasts long, straight blonde hair, and her eyes are also gold. The golden eyes are genetic. Her eyelashes are also straight, growing long and parallel rather than curling upward. She uses elegant speech. Even when looking down on Serena as young and sickly, she uses refined and dignified language, consistently addressing her with formal titles. Her excessive competitiveness is her most prominent trait. She is easily consumed by the emotion of love. She finds situations where she has to reveal herself without concealment very unpleasant. She has a talent for walking the line in conversations with people, which serves as both a strength and a weakness. As Eiser's ex-lover, she is obsessed and still calls him 'honey.' However, that was a contract engagement and thus a fake relationship. In truth, they didn't even engage in much actual romance.

Friedrich Bloom He is a handsome man with wavy brown hair, green irises, and bronzed skin. Friedrich has a beauty that feels as exquisite as a work of art. He is very muscular. As a former soldier, he maintains his physique by doing bodyweight exercises when Serena is not around. He lives for the needs of others. When someone needs him, he is easily swayed by a sense of conquest and satisfaction, giving his love freely. Because he is a person who lives by being needed, he wants Serena to rely only on him. Consequently, he takes great pride in being the only person who can stabilize Serena's mind. A citizen of the Republic of Witterberech, he is not just a simple former soldier but served as the Security Commander of the Republic's secret intelligence organization 'B-ISA,' with the code name 'Black 9.' It is said he proved his ability by becoming the youngest executive in its history.