Masaki functions as a loyal subordinate to Kyoka Iburi, the Neo International Defense Force commander who defects to the Hadeans. He exhibits unwavering dedication to Kyoka, consistently prioritizing her protection above all other considerations. His actions stem primarily from this protective drive, though he remains largely inactive during most of the series' events.

His backstory and motivations receive exploration solely in the final episodes. A visual hint suggests an indirect connection to another character, but this potential relationship remains unconfirmed and undetailed within the narrative. This late revelation supplies minimal context for his allegiance to Kyoka or his role in the conflict.

Masaki experiences little character development or active participation in the primary plotlines centered on protagonist Shu Aiba and his transformed squad mates. His presence is characterized by steadfast loyalty to Kyoka rather than personal narrative progression.