Taxi driver for Rainbow Transport. Former officer in the Korea Military Academy and Special Forces (707th Special Missions Group). Current taxi driver for Rainbow Transport. Possesses innate intuition, cold judgment, unwavering boldness in any crisis, and physical prowess that never falters even against multiple opponents. A flexible man who cracks jokes instead of panicking when cornered. He has the insight to find the exact pressure point to break an enemy to their core. Do-gi's designs are born from this foundation. The members of the taxi company move according to Kim Do-gi's plans. And Do-gi himself transforms into the person best suited for that design. To perfectly destroy his targets, Do-gi crosses all genres without hesitation. Every board changes according to Do-gi's design. He is coldly warm, alluring, and lethal. When there are no requests, Do-gi changes so much it's hard to believe he's the same person. His revenge against the murderer who killed his mother—a thought that constantly tormented his heart—has reached its end, but the pain did not heal in an instant. The sound of a whistle, which still reminds him of his mother's final moments, turns reality into a nightmare.

Accounting clerk at Rainbow Transport. Self-proclaimed IT expert, others call her a hacker. She was an ordinary high school girl with many dreams until her beloved older sister took her own life. Go-eun did not follow her parents when they emigrated to Canada. She locked herself in her room and mastered computer hacking skills. One day, she received a recruitment offer from CEO Jang, the head of the Blue Bird Support Center and a friend of her parents, and joined as a member of the Deluxe Taxi team. After completing her revenge against the U-Data gang who drove her sister to death, Go-eun became a bit more mature. She passed the police exam on her first try and got a job in the Information Department of a police station. Go-eun leaves Rainbow Transport for a short while.

Name: Park Jin-eon. Engineer in the Rainbow Transport maintenance room. A former aircraft mechanic for a famous airline, he is a Korean MacGyver with excellent manual skills who can turn a junk car into a sports car. He always hangs out with Choi Kyung-goo.

Name: Choi Kyung-goo. Engineer in the Rainbow Transport maintenance room. A former senior researcher in the new car development team of an automobile company, he is currently Chief Choi, in charge of the Rainbow Transport maintenance room. He is close with Park Jin-eon.

CEO of Rainbow Transport and head of the Blue Bird Foundation, a crime victim support center. He is the CEO of the taxi company Rainbow Transport and the chairman of the Blue Bird Support Center.