Mukyu Isurugi serves as a member of the Revisions, antagonists from a post-apocalyptic future. Her striking appearance includes dog ears, a tail, and a gothic lolita maid outfit—traits mirrored in her twin sister Chiharu. These features originate from temporary bodies selected by the twins for efficient human interaction, though they remain oblivious to the fanservice connotations of their aesthetic.

Mukyu’s personality balances cruelty and devotion: she exhibits sadistic ruthlessness toward Shibuya’s inhabitants, especially Nicolas Satō, whom she dominates and belittles due to her higher rank. Conversely, she demonstrates unwavering kindness and protectiveness toward Chiharu, underscoring a fierce loyalty to her sister. The Revisions’ survival hinges on harvesting human bodies as resources, a dire response to a degenerative plague that compelled them to replace their failing biology with cybernetics. Mukyu operates within this morally ambiguous framework, prioritizing the group’s collective survival over ethical constraints.

Her position in the Revisions hierarchy situates her above Nicolas but below other leaders, with her interactions frequently emphasizing tactical authority and pragmatic strategies. While her pre-Revisions history remains undisclosed, her actions align with the faction’s ideology of systemic human exploitation, viewing them as expendable components for sustaining their cybernetically augmented existence.