Torakichi Tanuki serves as deputy captain aboard the SS-99 submarine under Captain Kizuku Oyama’s command, aiding the crew in strategic clashes against the Ocean Empire’s forces. He collaborates closely with chief mechanic Susumu Oki and analyst Miyuki Moriki to execute high-stakes missions, including deep-sea combat operations and tactical engagements against hostile submarines. His role centers on coordinating critical maneuvers during battles at extreme oceanic depths, ensuring mission efficacy while supporting the submarine’s command hierarchy.