Nobuyuki Sakakibara, principal of Wakame High School, operates under the alias Tanaka "Susan" Fumiko during Sexy Commando missions. He conceals his identity with a red ski mask, primarily to evade recognition by Masaru Hananakajima. Before his tenure as principal, Sakakibara dominated the Sexy Commando circuit as Susan Fumiko Tanaka, securing six consecutive All-Japan Sexy Commando Tournament victories.

A pivotal moment reshaped his physical appearance when he expended all his energy to shift Wakame High School's building four inches off its foundation. This extraordinary feat triggered sudden, severe aging. He executed this action to inspire a then-unmotivated student, who later rose to become Japan's Prime Minister. As principal, Sakakibara covertly supports the Sexy Commando Club while maintaining his hidden dual identity among its members.

In extended media iterations, Sakakibara features as a playable unit where acquiring duplicate copies amplifies his abilities. Overcoming specific challenges unlocks a special costume that exposes his unmasked visage, deepening the exploration of his identity. His dual legacy as an educator and martial arts champion informs his mentorship of the club and his indirect guidance through the Susan persona.