Female. Late 20s. An enthusiastic, newly appointed Customs officer. Although GATE 24 is her first field assignment, she deciphers the truth from physical objects using her overwhelming powers of observation. She possesses an incredible depth of knowledge. When she focuses too intensely, she tends to forget rules and regulations, becoming oblivious to the voices around her.

Male. Late 20s. An Immigration officer. An elite career bureaucrat from the Ministry of Justice and a candidate for executive leadership. He volunteered for GATE 24 to gain field experience. An elite who pierces through to the truth of people based on law and data. He never causes trouble. He has excellent communication skills, though he uses them primarily as a survival tactic to avoid making waves within the organization.

Male. Early 20s. A young rising star and field-hardened Customs officer who joined after high school. He takes great pride in Customs being the nation's final line of defense and fulfills his duties with meticulous care. He can be stubborn and inflexible, occasionally clashing with the elite bureaucrat Hayami. However, through his kind nature, advice from trusted superiors, and his encounter with Machi, he grows into an exceptional Customs officer.

Female. Mid-20s. A national public servant belonging to the Animal Quarantine Service of the Ministry of Agriculture, Forestry and Fisheries. After graduating from veterinary school and obtaining her license, she became an animal quarantine officer. A modern young woman. While she can be hard to read, her work speed is astonishing. With calm judgment and high practical ability, she serves as the unsung hero of GATE 24.

Male. Early 50s. The Airport Director of Kanto International Airport. The field manager responsible for overseeing safe flight operations, air traffic control, and facility maintenance. He disapproves of GATE 24's existence, as its attempt to eliminate bureaucratic silos makes the chain of responsibility ambiguous.

Female. Late 20s. Ground staff. Machi's former classmate and best friend. Possessing a straightforward personality that hates lies, she is a great supporter of the eccentric and quirky Machi. She assists the GATE 24 team from the "front stage" of the airport lobby.

Male. Late 30s. Supervising Examiner. Although he serves as the leader of GATE 24, he is an unreliable middle manager who defers to Hayami or Fukasawa at every turn. He is the type to go with the flow and is unusually subservient to the elite Hayami. He has a gentle personality.

Female. Early 30s. An Immigration officer assigned to GATE 24. A non-career Senior Immigration Inspector. She has the ability to see the big picture and responds flexibly to changing situations.

Male. Early 60s. Chief Inspector of the Kanto Regional Immigration Services Bureau. Resonating with Midori's vision, he was invited to GATE 24 near his retirement age. Calm and soft-spoken, he is the kind, fatherly figure of GATE 24. He understands the weight of making judgments without illusions about human goodwill or malice. He supports the team with everything he has.

Female. Early 50s. Counselor at the Cabinet Secretariat's Border Management Reform Office. An elite bureaucrat who gave birth to this project, proposing GATE 24 to break down bureaucratic silos. She bets everything on GATE 24, trusting the members she hand-picked, including Fukasawa. She deeply trusts Fukasawa, who once taught her the ropes of field work. She maintains her own information network outside of official channels like foreign authorities and international organizations.