A 32-year-old male and the eldest son of the Akai family. He is an FBI agent and a master sniper. He wears a black beanie almost every single day; it is said to be rare to see him without it. He usually has a blunt and quiet personality. He frequently drinks canned coffee.

A 28-year-old male and the second son of the Akai family. He is exceptionally good at Shogi and possesses an incredible memory. His specialty is Shogi. He is usually kind and friendly, but he can be very serious at times.

An 18-year-old female and the third child of the Akai family. Her specialty is Jeet Kune Do, and she is a high school detective. She has a bright and cheerful personality.

A 53-year-old female and the mother of the Akai family. She rarely shows a smiling face to her children. She is an SIS agent.