Yuki exists across dual narratives within a post-apocalyptic OVA series set after an environmental catastrophe eradicated all human males and most females. As Yuki Ice-T, she is a polite, emotionally detached member of the non-blood-related Kisaragi family. She maintains consistently calm speech and reactions, even under immediate threat, and actively seeks friendship with the Guardswomen Captain upon meeting her, perceiving it as a shift in fate.

Simultaneously, she is the Guardswomen Captain, Hitomi Landsknecht. This battle-hardened leader suffers chronic insomnia, having gone three years without sleep. Commanding loyalty from subordinates like Murasaki, she navigates conflict between the Kisaragi faction—which accepts humanity's extinction—and Julia's faction, which pursues scientific survival through the "ICE" project. Her presence leads the military resistance against bioterrorism and ideological threats within ruined Tokyo.

Her background involves a mysterious temporal connection to Hitomi Aida, a pre-apocalypse woman who awakens in a hospital clutching an ornament identical to Yuki Ice-T's. This loop intertwines their fates, with Hitomi Aida's pregnancy echoing the series' themes of reproduction and survival. Yuki is positioned at the center of the struggle over the "ICE" specimen, representing humanity's last hope.

Her development includes confronting ideological adversaries, such as Julia's faction exploiting women for experiments, and grappling with her role in a dying world. Consequences of societal collapse are reflected indirectly through events like a child's skating injury within her ranks. The narrative culminates in her defiance against oppressive forces, though her ultimate fate remains unresolved amidst the ongoing conflict.