Daisuke Shima serves as the chief navigator and helmsman aboard the space battleship Yamato, entrusted with navigation, signaling, watch duties, and comprehensive route planning. He hails from generations of naval service; his father, Captain Daigo Shima, commanded the UNCN space cruiser Murasame and instilled in him the principle that a sailor never abandons a comrade in need. Growing up in Naha, Japan cemented his dedication to duty and loyalty to his crewmates.

During the voyage depicted in *Be Forever Yamato*, Shima's navigational expertise proves critical as the Yamato confronts the Black Nebula Empire. Discovering Lord Scaldart's time-travel plot revealing the Empire's origin as future Earth, Shima pilots the ship through the perilous Double Galaxy, demanding precision amid distorted spacetime and enemy assaults. His actions secure the Yamato's survival during the assault on Dezarium, disguised as Earth. Targeting the planet's core, Shima maintains course despite heavy damage to the bridge, enabling the decisive firing of the Wave-Motion Gun that destroys Dezarium.

Shima's character carries unresolved emotional conflict stemming from earlier events. In the original series' second season, he formed a deep bond with Trelaina, princess of Telezart, via interstellar communication. Her self-sacrifice to save the Yamato from the Comet Empire left him heartbroken, though he channeled his grief into renewed resolve to protect Earth. This history informs his steadfastness during the Dezarium crisis, where he balances duty with the weight of past loss. Following Dezarium's destruction, Shima continues as chief navigator during the Yamato's return to Earth, upholding his familial principles amid the conflict's aftermath.