Ryū Kamioka functions as assistant and follower to Momoko Prisilla, a wealthy dilettante determined to become the world's greatest actress and surpass Shiratori Nagisa as Japan's top idol. He regularly participates in Momoko's elaborate, unpredictable performances, which frequently involve bizarre or chaotic scenarios.

His core role involves supporting Momoko's endeavors, often plunging him into precarious or harmful situations due to the nature of her schemes. Despite the inherent risks and absurdity, he displays unwavering loyalty and dedication to her.

He actively attempts to learn from Momoko's acting approach and methodology, showing willingness to develop his skills under her guidance. His role remains consistently reactive to Momoko's initiatives, with no independent story arcs or significant evolution beyond this dynamic present in the material.

Ryū's presence fuels the series' comedic elements through his involvement in Momoko's reality-warping performances and the resulting chaos. The character lacks detailed backstory, physical description, or development outside his interactions with Momoko and his function within her entourage.