Natsume Sakasaki is a student at the idol training school Yumenosaki Academy and the son of a highly respected fortune-teller. He carries on the family tradition by practicing fortune telling alongside his idol activities, and he often speaks in riddles or utters mysterious, cryptic phrases. This enigmatic demeanor is paired with a sharp tongue and a contrary nature; he openly enjoys taunting both rivals and teammates with his eccentric behavior. Despite this playful, sometimes provoking exterior, he is deeply serious and hardworking, approaching his craft with genuine diligence. He is driven by a desire to conduct experiments and pursue the realization of his own ideals, a passion that fuels both his fortune telling and his stage work.

In the story, Natsume is recognized as one of the former Five Eccentrics, a legendary group of unconventional idols from the academy's past. He holds immense admiration for his fellow Eccentrics, particularly Wataru Hibiki, whom he reverently calls his master. This respect shapes much of his development, as he seeks to honor and carry forward the legacy of individuality and magic that the Eccentrics represented. Natsume eventually becomes the leader of the unit Switch, a group that presents itself as a team of magicians, showcasing a unique worldview through performances that blend stage banter with spectacular tricks. His role in the anime Ensemble Stars!! Tsuioku Selection Element places him directly in the narrative of the war era, exploring the relationships and conflicts among the five eccentric idols and the unit fine during that turbulent period. His abilities include fortune telling, sharp analytical thinking, and a commanding stage presence that makes his unit's magical shows both entertaining and cohesive.