Jill, once a lead creator and designer of Deca-dence, was labeled a "bug" by the system and exiled to the Bug Correctional Facility under undisclosed circumstances. Her human avatar boasts light mint-green hair, pink-hued skin, and pale blue eyes, clad in Deca-dence’s standard staff attire. Her compact cyborg body sports polka-dotted hair, a solitary eye, and round pink glasses.

Coolly analytical and sharp-witted, she communicates with blunt efficiency, often weaving philosophical insights into her dialogue. Though initially dismissive of fellow cyborgs in confinement, her interactions with Natsume spark a shift to genuine concern, later extending empathy to Tankers. Leveraging her insider knowledge as a former developer, she breaches Deca-dence’s systems and alters cyborg mechanics despite imprisonment.

She shares a dynamic rapport with Donatello, the facility’s unofficial leader, becoming one of the few who can disarm him with humor or spur him to act. Intrigued by Kaburagi’s history and goals, she deploys her technical mastery to aid his rebellion. Amidst the clash against the mutant Gadoll and Solid Quake’s plot to dismantle Deca-dence, she secures Kaburagi’s data, ensuring his resurrection three years after his demise.

Her journey transforms her from a confined ally to a linchpin of systemic resistance, harnessing engineering prowess to orchestrate key tactical wins. This arc marks her shift from a disillusioned outsider to a decisive force dismantling Deca-dence’s tyranny.