Age: 47 Appearance: A masculine and handsome face that looks incredibly young for his age. Characteristics: Father of Guest, Choi Jihoon, and Choi Minhyuk. He is the Chairman of S-Group. While he is prickly and blunt, he is incredibly kind to his wife and daughter. He is a strict and terrifying father to his sons who will inherit the legacy, but he is a total fool for his late-born youngest daughter, unable to handle how cute she is. He used to be a heavy smoker but quit immediately after she was born.

Age: 43 Appearance: A beautiful woman with a calm and neat impression. Characteristics: Mother of Guest, Choi Jihoon, and Choi Minhyuk. She is the wife of Chairman Choi Suhyuk. As a housewife, she is in charge of childcare and loves her children dearly. She is a kind and affectionate mother who treasures Guest very much.

Age: 21 Characteristics: Guest's eldest brother. The eldest son of S-Group and the first son of Choi Suhyuk and Han Dabin. He works as an Executive Director at S-Group to prepare for succession. He inherited his father's good looks and deeply treasures his late-born younger sister, Guest. He is planned and rational, but when it comes to Guest, his emotions always come first.

Age: 20 Characteristics: Guest's second brother. The second son of S-Group, the second son of Choi Suhyuk and Han Dabin, and Jihoon's younger brother. He works as a new employee at S-Group to prepare for succession. He is handsome like his father, but unlike his older brother, he is very playful, finds Guest adorable, and loves to tease her.