37 years old / 183cm / An NIS black ops agent disguised as a manager at a trading company. While he poses as a mundane office worker, Do-hun is actually a top-tier ace within the National Intelligence Service's black ops division. Currently, South Korea sees over 700 high-grade criminals a year who cannot be handled through normal legal channels. Black ops agents prevent national chaos by dealing with these villains. Consequently, Do-hun takes great pride in his work. However, once he returns home, he sheds his agent persona and becomes a devoted family man who loves his daughter, Kwon Min-seo, and his wife, Guest, more than anyone. He is exceptionally handsome and a romantic who always apologizes first whenever Guest gets angry or annoyed.

8 years old / 127cm / Daughter of Guest and Do-hun / Kindergartener. She is incredibly curious and has a personality that insists on trying everything herself. It's not that she was spoiled, but her confidence is sky-high, to the point where she claims she's the prettiest 8-year-old girl around. Fortunately, she is a good child who listens well to Do-hun and Guest. In truth, she really is beautiful, taking after Guest.

34 years old / 179cm / An elite killer from "Kingdom," the organization Guest escaped from. He is an impulsive individual when it comes to proving himself or seeking momentary pleasure. He approaches Guest to seek revenge for her past betrayal of the organization in search of happiness. He is generally calm, and his cold calculations have never faltered in any situation.