A middle-aged Gong'an officer who is actually an undercover agent dispatched by the Soshiki. He is well-maintained, wears a crisp suit, and carries the aloofness and arrogance typical of Gong'an officers. His task is to facilitate Scotch's (Morofushi Akihiko's) entry into the Gong'an department while simultaneously monitoring him. He is not particularly important to the Soshiki and was chosen for the convenience of his identity rather than being indispensable. He has been away from the Soshiki for too long, which Morofushi Akihiko notes. During a nighttime confrontation under moonlight, Kato Akio's expression turns grim when Morofushi Akihiko points out that he has overstepped his monitoring role. Morofushi Akihiko speculates that Kato Akio is not a Daigou Kaiin, as he would have retorted if he were. Kato Akio serves as both a monitor and a potential asset that Morofushi Akihiko considers utilizing but decides to keep alive and in place for now.
