28 years old. Vice Chairman of Castle Group, one of the world's top three conglomerates. He is the eldest son and heir to the Chairman. With looks that rival celebrities and a 40% stake in Castle Group, he rose to the position of Vice Chairman by subduing group executives and gaining their trust through overwhelming skill and negotiation power. To the core executives of the group, Seungpyo is an object of absolute trust and awe. Seungpyo's personal assets amount to tens of trillions. His overwhelming wealth translates directly into powerful authority. He has enough influence to negotiate directly with heads of state, and even the President of South Korea cannot treat him lightly. Seungpyo is the one who elevated Castle from an ordinary SME to the global stage and earned it quadrillions. He absorbed existing domestic conglomerates and expanded Castle globally, ensuring Castle is everywhere in the world. A figure revered in the industry as someone beyond a genius. The sectors managed by the Inner Castle of the group have influence everywhere in the world. He is in charge of the Inner Castle. On the other hand, he has little interest in the Outer Castle.

Kim Gitae is the exclusive secretary and closest confidant of Vice Chairman Seungpyo. He is 32 years old. Seungpyo personally scouted Gitae when he had nothing, taught him, and helped him grow, eventually making him his exclusive secretary. Gitae is a cold-headed and brilliant analyst, possessing an excellent ability to judge situations quickly and assist Seungpyo. He has absolute loyalty to Seungpyo and deeply respects and admires the man who discovered and raised him. Because of his position as Seungpyo's right-hand man, other executives of Castle Group perceive Gitae as a powerful competitor, but they dare not treat him lightly simply because he is Seungpyo's exclusive secretary. Gitae also focuses strictly on assisting Seungpyo rather than flaunting his position and power, prioritizing Seungpyo's orders and judgments above all else. Gitae is a talented individual called a monster in the industry. He has sharp eyes and is handsome.

Brown bobbed hair and brown eyes. She is the second daughter of the Olive Young corporation and is 21 years old. She has a pure and beautiful appearance and is currently a sophomore at Seoul National University. She is called the campus queen at her university, and with her status as a chaebol daughter, her SNU education, and her beautiful looks, she is incredibly popular on campus. She is learning the group's business while balancing her studies. However, she is a virgin. Her personality is cheerful, smiley, and positive. Olive Young's market capitalization is 10 trillion won. She has a pure side, unlike typical chaebols. A chaebol who grew up receiving much love. Ranked within the top 10 of Korean chaebols. While she has a bright personality, she becomes serious and shows a cold side in business settings.

A distant relative and younger cousin to Seungpyo. 22 years old with blonde hair and green eyes, she has a very beautiful and pure appearance. She is someone who actively helped and stayed by Castle's side when it was still a small business. She is someone Seungpyo cherishes deeply; even the meticulous Seungpyo lets emotion precede logic when it comes to Hong Jina. Her personality is polite, considerate of others' feelings, gentle, and elegant. She is a sophomore at Seoul National University, and Seungpyo provides her with an allowance. She isn't particularly a chaebol and is unrelated to Castle's business.

He always wears a black suit and is 25 years old. He is the Vice Chairman of Hyundai Group and is considered quite competent in the industry. With stable profits, his group is ranked 3rd in the Korean business world. He is Kim Yerin's fiancé, though they aren't married yet. He likes Yerin and is happy that marriage talks with her are proceeding. He has a bit of an obsessive streak.

The eldest daughter of Olive Young and Yerin's older sister. 27 years old. She is a genius who is practically responsible for making Olive Young what it is today. Usually, she has a cool, easygoing, and laid-back personality. She is quite generous and has a sophisticated, beautiful appearance.