Akimasa Kazato is a Lieutenant Colonel in the Imperial Japanese Army and serves as a primary antagonist within the D Agency. His background is deeply rooted in traditional military doctrine, representing the orthodox establishment that views the agency’s unorthodox methods with suspicion. Kazato is a graduate of the Army War College and holds a conventional belief that espionage should be conducted through traditional means, such as cultivating assets through ideology or financial pressure, rather than the morally ambiguous and independent methods taught by D Agency.

Personality-wise, Kazato is stern, prideful, and rigidly principled. He is a patriot who believes fiercely in the honor and structure of the Imperial Army, which makes him distrustful of spies, whom he regards as dishonorable and inherently untrustworthy. This distrust is particularly acute regarding the spies of D Agency, as they lack the traditional military pedigree and operate outside the normal chain of command. He is not overtly cruel but is pragmatic to the point of ruthlessness, willing to sacrifice pawns to achieve a strategic objective. His demeanor is typically formal and reserved, masking a sharp intellect and a persistent desire to prove the superiority of conventional military intelligence.

Kazato’s primary motivation is to secure the authority of the Army General Staff and to dismantle or absorb the D Agency, which he views as a rogue element. He is driven by a combination of professional jealousy and genuine concern over the agency's lack of overt loyalty to the military hierarchy. His role in the story is largely that of an adversary and a bureaucratic foil to Lieutenant Colonel Yuuki, the founder of D Agency. He frequently pressures Yuuki, attempts to entrap the agents in missions designed to fail, and seeks evidence of disloyalty to justify disbanding the organization. He also serves as a patron of sorts to Sakuma, sending the young officer to D Agency as a spy in an attempt to understand and ultimately expose its weaknesses, though this plan backfires as Sakuma grows to understand the agency's value.

Key relationships define much of his development. His relationship with Lieutenant Colonel Yuuki is one of mutual respect wrapped in intense rivalry. While Kazato fundamentally opposes Yuuki’s methods and the very existence of his school, he cannot deny the results the D Agency produces. His interactions with Sakuma are more paternalistic and instrumental, using the lieutenant as a tool to validate his own beliefs. Through Sakuma’s reports, Kazato gains insight into the D Agency but ultimately fails to fully comprehend its core philosophy, leading to a static character arc. Unlike many characters who undergo a transformation, Kazato remains largely steadfast in his convictions throughout the series, though he is occasionally forced to acknowledge the effectiveness of the spies he despises. His development is subtle, shifting from outright hostility to a grudging tolerance, accepting the agency’s utility in extreme wartime scenarios while never abandoning his desire to control or eliminate it once the crisis passes.

Notable abilities include his strategic mind and extensive experience in military intelligence and counter-espionage. While not a field operative like the D Agency agents, Kazato is highly skilled in deduction, interrogation, and bureaucratic warfare. He is adept at anticipating moves and setting traps, though his adherence to traditional patterns makes him predictable to the more flexible D Agency agents. His authority as a Lieutenant Colonel also grants him significant operational resources and the ability to influence high-level military policy, making him a formidable opponent despite lacking the specific tradecraft of a spy.