Detective Tokuno is a seasoned investigator serving with the Criminal Affairs division at the Bokuto Police Station. His official rank is that of Inspector, which establishes him as a figure of significant authority and experience within the precinct. Tokuno is a man who typically appears calm and composed, a characteristic often visually represented by his perpetually narrowed eyes, though he is known to open them fully on occasion for emphasis. He is also depicted as a heavy smoker.

In terms of personality, Tokuno projects a steady and dependable presence. He functions as a reliable source of support for the station's Traffic Division, frequently requesting their assistance on cases. These requests usually arise for a few specific reasons: when an operation requires a larger number of personnel than the traffic unit can muster, when the unique skills of officers like Natsumi Tsujimoto and Miyuki Kobayakawa are necessary, or when a case has elements that directly involve traffic matters. Despite his serious profession, he has a friendly and somewhat informal side, demonstrated when he brings taiyaki, a popular fish-shaped cake, to share with his colleagues at the station. He also enjoys friendly but competitive games of Go with the chief of the Traffic Division, a contest he often wins.

Motivation for Tokuno is rooted in his dedication to solving serious crimes and maintaining order. He is a capable investigator who frequently provides crucial clues, coordinates undercover operations, and gathers vital intelligence to resolve major cases. His commitment to justice is unwavering, and he has shown a willingness to trust the instincts of his officers, going so far as to risk his own career on the judgment of Officer Miyuki Kobayakawa. This demonstrates a deep professional respect and trust in the abilities of those under his purview.

Tokuno's role in the story is as a key ally and superior to the main cast, often bringing them into the fold when his criminal investigations intersect with their traffic patrols. He works closely with his direct colleague, Detective Sugihara, who is also from the Criminal Affairs division and tends to be more easily startled by dangerous situations. His relationship with the Traffic Division, especially its chief, is one of close professional rapport and mutual respect, to the point that Natsumi once rallied the entire traffic department to challenge Tokuno's division to a baseball game to help their chief finally win a Go match against him. He is also aware of Natsumi's fondness for older men, though unlike the single chief of traffic, Tokuno is a married man.

Throughout the series, Detective Tokuno demonstrates notable professional development, particularly in adapting to new technology. Initially described as severely illiterate with computers, he makes an effort to learn how to use them alongside the younger officer Ken Nakajima. His abilities extend beyond detective work; he is highly proficient in martial arts, excelling in both judo and kendo, which makes him formidable in physical confrontations. He is a central figure during major incidents, such as the investigation into illegal gun trafficking and a plot to blow up a bridge, where he actively directed operations and coordinated with other units to subdue criminals. His experience and judgment make him a cornerstone of the Bokuto Police Station's efforts to combat serious crime.