Diana, Elaine’s older sister, endures illegal experiments alongside her sibling, designed to unlock psychic abilities and forge super-soldiers. Crippled physically and dependent on cybernetic enhancements, her considerable psychic powers pale against Elaine’s raw strength, igniting bitter jealousy and resentment. Their abusive guardian—a mad scientist who prizes Elaine as his ultimate weapon—intensifies this rift through open favoritism.

Tasked with controlling Elaine, Diana’s attempts to dominate her sister repeatedly falter. A climactic rage-driven confrontation seemingly kills Elaine, but her consciousness survives, merging with Diana’s cybernetic form to birth Genocyber—a biomechanical entity of colossal destruction. Trapped within Genocyber’s collective consciousness, Diana’s agency is suppressed, her psyche imprisoned alongside her sister’s.

Post-merger, Diana’s physical form fades, yet her influence lingers. Centuries after Genocyber’s initial rampage, she resurfaces as a spectral figure contacting Mel, a blind woman in a post-apocalyptic city. Addressing Mel as “Big sister,” Diana implies a metaphysical bond. This encounter coincides with Genocyber’s resurgence, suggesting her consciousness remains entwined with Elaine’s within the entity.

Adaptations diverge in Diana’s portrayal: the manga depicts her as fragile yet compassionate, while the OVA recasts her as vengeful and manipulative, consumed by envy and parental neglect. Her cybernetic body, once vital for survival, becomes a prison as Elaine’s dominance within Genocyber sidelines her. Nevertheless, Diana’s residual psyche influences Genocyber’s final rampage—destroying the City of the Grand Ark and triggering the enigmatic rebirth of Mel’s child, who may harbor echoes of both sisters.

Diana’s arc weaves themes of exploitation, corrosive sibling rivalry, and eroded autonomy. Her evolution from vulnerable test subject to a splintered presence within Genocyber underscores the tragic fallout of unchecked human experimentation and ambition.