OVA
Description
Eva Maria Parrales, designated Cyborg 0015, was born with her brother Seth in a Canadian Black Ghost facility experimenting on mutant children. After Seth fell comatose, Dr. Adams Teufel took him for the "Cyborg Demon" project, convincing Eva it would cure him.

Adopting the alias Eva Maria Parallels, she traveled to Japan as a transfer student. Her quiet, observant nature concealed her mission: to befriend Miki Makimura and Akira Fudo while tracking the human fused with the demon Amon. Eva showed curiosity about Miki's ordinary family life, contrasting her own isolated upbringing.

Following Dr. Adams's orders, Eva abducted Miki to lure Akira and Ryo Asuka to Black Ghost headquarters. Though complicit, she aimed to prevent harm to Miki. Inside the facility, Eva witnessed Seth forcibly merged with the demon Atun, designed by Dr. Adams to erase Seth's mind. As Atun seized control of her brother's body, Eva transformed into Cyborg 0015, instantly clad in a black uniform with silver accents, a white scarf, and red seams.

Eva fought the Atun-possessed Seth but was overpowered and gravely injured. Discovered by Devilman, she was violently discarded. Regaining consciousness, she attempted to rescue Miki, only to be intercepted by Ryo Asuka. During their battle, Eva collaborated with Dr. Gilmore to activate an EMP wave, disabling the self-repair systems of the High-Teen Number cyborgs. This unintentionally caused Atun to evolve into the more powerful entity Azazel.

As a final act, Eva utilized astral projection, aided by Cyborg 001, to reach Seth's consciousness within Azazel. Her soul separated Seth from Atun, allowing Seth's soul to depart peacefully. This effort fatally strained Eva's already injured body combined with the astral projection's toll. At dawn, she was found frozen on her knees, deceased, wearing a tearful smile. Her death symbolized freedom from Black Ghost, represented by doves flying into the sunrise alongside Seth's soul.

Eva possessed a slender build, light blonde hair extending past her waist usually held by a pale blue headband, and dark blue eyes lacking visible sclerae, appearing to sparkle. In her civilian guise, she wore a gray vest, a white sailor-collar blouse, a black pleated skirt, knee-high stockings, and brown loafers. Her cyborg transformation allowed instant adoption of the uniform via disguise shedding.

Driven by devotion to Seth, Eva balanced manipulation with protectiveness. She cooperated with demons and Black Ghost out of desperate hope to save her brother but resisted unnecessary cruelty. Her actions culminated in sacrificing herself to free Seth's soul, accepting death as redemption for their shared trauma. While her final seated posture led some interpretations to suggest ambiguous survival resembling deactivation, the narrative context indicates her physical demise.