Mau Sakisaka, a Japanese naval cadet, shares a romantic connection with protagonist Shiokaze Umino, directly influencing her decision to enroll at Nakano Naval Academy. Her enrollment centers on proving her virginity to meet societal standards for marriage, framing Mau as an emblem of traditional expectations surrounding purity and matrimony.

Acting as a mediator in academy disputes, he attempts to reconcile tensions between Shiokaze and Satsuki Yukimizawa, the cadet leader fiercely committed to preserving the Virgin Fleet’s strategic integrity. His well-intentioned yet bumbling efforts frequently amplify interpersonal clashes instead of diffusing them. During external crises—such as enemy espionage targeting the fleet—his exchanges with Shiokaze underscore her conflict between romantic ambitions and duty to the military.