Isao Oki is a high-ranking official in the Japanese government organization tasked with securing and deploying the stolen mecha Zeorymer of the Heavens against the Hau Dragon faction. His duties center on managing Zeorymer's pilot, Masato Akitsu, and its vital support system, Miku Himuro.

He supervised an experimental procedure that forcibly accelerated Miku Himuro's physical maturation from childhood to adulthood. During this process, Oki impassively monitored her visible distress while she was restrained in an isolated chamber with electrodes attached to her body, demonstrating his operational priorities superseding ethical concerns to ensure her functionality within Zeorymer's control system.

Oki's responsibilities also include tracking Zeorymer's combat engagements and maintaining strategic oversight of the weapon system's deployment against Hau Dragon forces.