Yasuo Nanbu, born July 28, 2177, is the heir to Nanbu Heavy Industries, a major munitions company significantly influencing Earth's military economy. Despite objections from his family, particularly his father Kozo, he chose to join the UNCN military service, creating persistent friction that grew increasingly strained.

He served as the main gunner aboard Space Battleship Yamato during its initial voyages, part of the tactical division under Susumu Kodai's command. Nanbu oversaw the performance and deployment of weapons systems, including ship cannons and missiles, directly supporting tactical operations during key battles against Garmillas forces.

Nanbu later transferred to the supply carrier Asuka, advancing to Executive Officer and Chief Tactical Officer. In this leadership role, he supported Captain Yuki Mori, providing tactical expertise and operational oversight. His responsibilities included coordinating the vessel's defense systems and combat strategies. His documented service concludes with this assignment aboard Asuka, supporting Earth's defense forces during the period depicted in Yamato 2205.