Yonari Kaihara operates across dual narrative layers in the franchise. She is a fictional character within the in-universe theatrical production "Alice in Deadly School," performed by the cast of the "Gekidol" anime series. In this play's narrative, Yonari appears among schoolgirls trapped on their rooftop during a zombie outbreak, where planning survival and navigating friendships become crucial.

Simultaneously, the name and narrative identity of Yonari Kaihara are shared by an entity in the broader "Gekidol" universe. The main series character Tomoko Hinata portrays the role of Yonari Kaihara during performances of "Alice in Deadly School." This creates a dual existence where Yonari manifests both as a persona within the internal stage fiction and as a role enacted by a persistent character in the primary narrative.

The documented materials provide no additional background, development, specific actions, personality traits, or narrative evolution for Yonari Kaihara beyond this structural interplay between the theatrical fiction and the overarching series universe.