Yumemi Hoshino appears as a supporting character in the crossover series, adapted from her original role in Planetarian. Her design simplifies into a super-deformed chibi style consistent with the series' aesthetic, maintaining her light blue hair and green eyes while omitting her signature ribbon. Within this multiverse setting, she functions primarily as an observer of the interconnected world alongside Ushio Okazaki. Positioned within a planetarium, they act as narrative anchors, commenting on the world's stability and interconnectedness from their observational vantage point. Her personality reflects her original programming as a robot attendant—persistently upbeat, polite, and dedicated to serving guests. These traits emerge through a comedic lens due to her obliviousness to the absurd events surrounding her. Her background as a gynoid from a post-apocalyptic planetarium remains unexplored in depth, though her core directive to protect humans and provide service persists as a recognizable trait. This surfaces subtly in her interactions and through the reuse of her iconic line about heaven: "Please do not divide the robots from the humans." The series repurposes this philosophical statement as part of its broader meta-humor and thematic exploration of coexistence. Distinct from characters engaging in direct comedic antics, her role remains largely passive and symbolic. She embodies a beacon of hope and continuity from her source material, contrasting with the chaotic interactions of other characters. Her presence underscores themes of legacy and the preservation of innocence within the collective Key universe.