Kōsaku Ōmura holds the critical role of chief engineering officer aboard the Space Battleship Yamato, tasked with maintaining and repairing its advanced systems—from weaponry to engines—while strategizing technical solutions under extreme pressure. His meticulous nature and unwavering dedication drive him to prioritize the ship’s survival and crew safety, often sidelining personal needs. Initially conceived through the merger of two distinct roles, his original narrative involved a sacrificial gambit: piloting a detachable ECI (Emergency Combat Interface) room module designed to operate independently in combat. This concept was later streamlined to amplify Ōmura’s centrality, rendering the ECI separation obsolete.

Haunted by unresolved trauma from past losses, his composure fractures during clashes with hostile forces, revealing vulnerabilities beneath his stoic exterior. Yet his loyalty to the Yamato’s mission and crew remains unshaken, evidenced by relentless hours spent ensuring operational readiness in the engine room. Analytical and risk-averse, he navigates technical challenges with precision, though simmering anxiety occasionally tests his resolve.

During the Third Emigration Fleet’s perilous mission, his ingenuity becomes indispensable in thwarting SUS-led Alliance assaults, safeguarding civilian arks through adaptive tactics. These actions cement his reputation as a steadfast pillar amid turmoil, blending technical mastery with quiet resilience to anchor the crew through chaos.