Hayato Nangō is the Executive Officer of submarine 707, operating under Captain Youhei Hayami. Beginning his career as a third-grade officer in the Maritime Self-Defense Force, he rises through the ranks to second-grade officer before securing command of submarine 717. As XO, he partners closely with Captain Hayami to counter threats to maritime security, spearheading tactical decisions during high-stakes clashes with adversaries like the Undersea Silence Revolution and its enigmatic leader, Admiral Red. Nangō’s evolution from disciplined subordinate to decisive commander underscores his strategic prowess and capacity to adapt under pressure. His unwavering loyalty to his crew and relentless focus on defending oceanic stability drive his ascent, culminating in his eventual leadership of the 717—a role that solidifies his legacy within the fleet’s operational hierarchy.