Daisuke Yamanaka is a 45-year-old former model who rose to prominence in his youth only to be expelled from the industry for his brash behavior. After his dismissal, the previous president of Manpuku Entertainment Productions hired him as a manager in the Management Department, an act that instilled in him a powerful sense of gratitude. This debt forged a profound sense of duty and responsibility, along with a resolve to dedicate his life to the company's success.

He later joins the Eternal Boys idol group as part of the agency's initiative to stage a comeback. His given name, Daisuke, conveys meanings of "big" or "great" and "help," while his surname, Yamanaka, means "mountain" or "hill" and "middle," reflecting his steadfast and supportive nature.