Professor Oki, a human scientist aligned with government forces, conducts the interrogation of protagonist Hiroshi Umino after an attack on an ocean structure, pressing him for details about a mysterious battleship. This occurs under government authorities probing the conflict between humanity and the ocean-dwelling civilization.

He later reports to the battleship commanded by Doctor Zelvado, indicating collaborative or subordinate ties to military leadership. During this interaction, he observes the emergence of Izanami—an alien entity linked to the undersea civilization—on the battleship’s communication screen. His presence during this event positions him within the command structure confronting the oceanic revolt.

His actions consistently reinforce the human government’s campaign to suppress the ocean people’s uprising. Operationally, his involvement focuses on intelligence extraction through Hiroshi’s interrogation and direct coordination with Zelvado’s militarized response to assaults on surface installations.