Daisaku Nishikawa operates as the Battle Team's third member, consistently identifiable by his brown combat attire. He commands the Battle Tank, which constructs Combattler V's torso and possesses no independent flight capacity, necessitating aerial transport by other team vehicles. His background includes judo mastery, demonstrating significant physical strength, yet he maintains a gentle and kind-hearted nature that embodies the Gentle Giant archetype. An accomplished sketch artist, he adds a Cultured Badass dimension to his persona.

Daisaku exhibits strong bonds with his teammates, especially Kosuke Kita, with their mission interactions underscoring his supportive role and mentorship dynamic. His machine provides tactical versatility, enabling defensive excavation maneuvers during crises like a volcanic threat to the team's base. Across documented series and media, his narrative remains consistent as a reliable Combattler V pilot without significant personal evolution or expanded backstory.