Hayami is a supporting antagonist in the anime Zetman, recognized as a trusted assistant and key advisor within the Amagi Corporation. He is frequently seen at the side of Kouga Amagi, the heir to the powerful Amagi family, for whom he acts as a handler and consultant. His exact origins and history before joining the Amagi Corporation are not deeply explored, but his position and actions throughout the story reveal him to be a long-standing and embedded member of the organization.

In terms of personality, Hayami is calm, collected, and perpetually professional. He maintains a composed and rational demeanor, often appearing as a voice of level-headed logic in contrast to Kouga's more passionate and idealistic nature. He is an extremely shrewd and observant individual, capable of manipulating situations and people with subtlety. Beneath his loyal and helpful exterior lies a calculating and ultimately treacherous nature. He is patient, willing to bide his time and work from the shadows to achieve his own goals. His actions are driven not by the same sense of justice as Kouga, but by a cold, pragmatic self-interest.

Hayami’s primary motivation appears to be his own survival and advancement. He is revealed to be aligned not with the Amagi family, but with the series’ primary antagonists, including the enigmatic businessman Seizou and the rogue scientist Jirou. He participates in elaborate schemes designed to destabilize the Amagi Corporation and psychologically torment Kouga, suggesting a deep-seated agenda against the family he pretends to serve. He is a willing participant in plans that involve unleashing dangerous creatures known as Players and orchestrating no-win scenarios for Kouga, indicating a malicious and opportunistic core. He seeks to use the chaos to his own benefit, turning against the Amagi family when it suits him.

In the story, Hayami’s role is that of a wolf in sheep's clothing. He is situated as a close and seemingly indispensable aide to Kouga Amagi, a young man burdened with the legacy of being an Alphas, a bio-enhanced soldier. For much of the narrative, he appears to be a helpful and pragmatic supporter, giving Kouga advice on the difficult choices a hero must make. However, this is a facade. His true role is that of an agent working to break down Kouga’s spirit and ideals. He serves as a key instrument in the villains' plan to expose Kouga to impossible moral dilemmas, such as forcing him to choose who to save during a crisis, all with the intent of proving his heroic ideals to be hypocritical and hollow.

Hayami’s key relationships are central to his duplicity. His most important relationship is with Kouga Amagi, the young hero he is tasked with manipulating. He is shown to have a close working relationship with the rogue scientists Jirou and the corporate figure Seizou, conspiring with them against the Amagi family. While his direct interactions with the series' protagonist, Jin, are minimal, his machinations are partly designed to affect the world in which Jin exists. His relationship with the Amagi family is ultimately one of betrayal, as he works alongside their enemies to bring about their ruin.

The character’s development is marked by the revelation of his betrayal. He spends much of the series building trust, only to reveal his true colors in a critical moment. When he finally discards his facade, he shows himself to be a cowardly and desperate man. After his schemes are exposed, he attempts to use a captured father and son Player team as leverage against Kouga, threatening to kill them to force Kouga's compliance. In a sudden and decisive turn of events, Kouga rejects Hayami's manipulation and kills both Players before fatally shooting Hayami himself. This moment serves as the end of Hayami's arc, where his treachery is met with the very violence and pragmatism he helped to foster in Kouga.

Regarding notable abilities, Hayami does not possess any superhuman powers or combat enhancements like the Zetman or the Alphas. His strength is entirely non-physical. His notable ability is his intellect and his talent for psychological and corporate manipulation. He is an expert at reading people, exploiting their weaknesses, and maintaining a convincing persona of loyalty and competence. He is a strategist who operates from the shadows, using his position and his knowledge of the Amagi family's secrets to orchestrate events from within. His power lies in deception, planning, and his ability to orchestrate the downfall of those more powerful than himself through cunning rather than force.