In a post-apocalyptic world where men face extinction due to environmental contamination, Kisaragi commands the influential Kisaragi family. Her genetic engineering—a fusion of human and jellyfish DNA—manifests in stark physical traits: pale white skin and long white hair.

She champions acceptance of humanity's inevitable demise over scientific intervention for survival. This philosophy directly opposes factions like the Guardswomen, who deploy the biological weapon "ICE" to perpetuate the human race, igniting the narrative's central conflict.

Kisaragi's origins as a genetic experiment shape her conviction that humanity's downfall stems from inherent flaws, particularly the destructiveness of male-dominated societies. She advocates peaceful resignation to extinction, viewing further struggle as futile.

She adopts Yuki Ice-T without blood relation, integrating her into the Kisaragi household. Yuki's interactions, including those with figures like Hitomi Landsknecht, reveal ideological clashes between Yuki's yearning for connection and Kisaragi's detached acceptance of fate.

The Kisaragi family's conflict with the Guardswomen peaks in battles over ICE control. Kisaragi remains unwavering throughout, embodying the narrative's thematic tension between resignation and resistance. Her hybrid existence and leadership role cement her as a symbol of humanity's past genetic experimentation consequences.