Julia commands the Guardswomen, a paramilitary force in post-apocalyptic Tokyo following male extinction. She leads the Red Roses faction, ruling subordinates tasked with testing the ICE project and fulfilling her personal needs—both sexual interactions and routine duties. Her appearance features long, waist-length blonde hair, green eyes, and an elaborate military uniform.

Her driving objective is securing ICE technology, believing it essential for humanity's artificial reproduction and survival. This directly opposes the Kisaragi family's acceptance of extinction. To ensure loyalty, she promises Guardswoman Aoi future pregnancy through ICE. Julia employs extreme methods, including violence and coercion, removing any obstacle to her goals and positioning her as a well-intentioned extremist.

Her leadership blends hedonism and manipulation; she surrounds herself with maids for service and personal gratification, consistently using others for her purposes. Antagonism toward the Kisaragi family fuels conflict as she aims to weaponize ICE against their ideology of embracing humanity's end.

A critical turning point occurs when Julia locates and activates what she believes is an ICE production facility. Instead, Kisaragi's deception reveals it as a terraforming superweapon. Her action unwittingly unleashes this device, accelerating the very catastrophe she sought to prevent. The narrative provides no explicit details about her origins, upbringing, or life prior to the apocalypse.