Mii is a student at the school and a core member of the Manga Research Club alongside Ai and Mai. She is a childhood friend of Mai and shares the same class with Ai. Her background does not receive extensive elaboration, but her long-standing friendship with Mai forms a foundation for her interactions.

Personality-wise, Mii is highly eccentric and often the instigator of the group's most outlandish and extreme antics, frequently taking them to levels not condoned even by her equally whimsical friends. She tends to present herself as bold and fearless, yet her behavior reveals moments of cowardice when genuine danger arises. Her motivations appear rooted in a desire for chaos, competition, and amusement, and she shows virtually no interest in the actual club activity of drawing manga. Mii's role in the story is to serve as a primary engine of surreal and dark comedy, escalating mundane incidents into absurd, violent, or hallucinatory scenarios. She is a constant source of unpredictable energy that disrupts any attempt at normalcy.

In terms of key relationships, Mii shares a competitive yet inseparable bond with Mai, with the two frequently trying to outdo each other in outrageousness. She often tests the patience of Ai, who tries to maintain order, but Mii's antics are so persistent that Ai occasionally becomes complicit. Mii regards the upperclassman Ponoka with a mix of respect and wariness, as Ponoka's own bizarre behavior can outstrip even Mii's.

Mii undergoes little to no character development over the course of the series; she remains a consistently chaotic force whose personality and attitudes do not meaningfully evolve. Her most notable attributes are her ability to undergo extreme physical transformations, enter surreal dreamscapes, and display a sort of masochistic resilience to harm, all of which are used exclusively for the series' absurdist comedy. These traits are not presented as genuine superpowers but as part of the show's deliberately illogical and gag-driven tone.