Rū Asuka is a human female idol with distinctive blond hair, blue-grey eyes, and a noticeable fanged tooth at the corner of her mouth. She performs as part of the devil-themed unit Oshama Tricks alongside Devi Fudo, their stage names combining to form the word "devil"—with Rū contributing the "L".

Oshama Tricks debuted in Episode 26 ("We Tried Playing Strange Pranks!") by executing pranks on fellow idols, specifically targeting the group Meltic StAr. This introduction established their signature mischievous style within the series' streaming framework. Rū embodies this role energetically, displaying playful behavior during performances and interactions.

Her classmate Hikari Momoyama frequently lectures her about her conduct, creating an ongoing dynamic between them.