Cornelius Stirk

Created by Alan Grant and Norm Breyfogle, Cornelius Stirk first appears in Detective Comics #592 (November 1988). In continuity he was confined from age 16 after attempting to kill a classmate, later certified as sane and released (Detective Comics #592), then ceased taking prescribed medication and resumed violent cannibalistic killings. Across subsequent storylines he is repeatedly re-incarcerated at Arkham Asylum and later held at Blackgate Penitentiary, appearing in arcs including Knightfall and various Shadow of the Bat / Batman issues cited in the DCU indexes and story archives.

Depicted as a gaunt human male shown in psychiatric/inmate settings (Arkham, Blackgate) and artwork by his creators; specific canonical panel-by-panel physical metrics are not provided in the cited summaries. His most salient visual trait in-story is that victims perceive him as other people — often a trusted face — due to his hypnotic aura, so his apparent visage varies according to observers' hallucinations (example: Commissioner Gordon hallucinates Stirk as Batman during an attack in the Knightfall-era encounter).

Stirk generates a hypnotic/telepathic aura that induces fear and perceptual hallucinations, allowing others to see him as 'any face he chooses,' typically someone they trust. This ability is presented as a psychic/perceptual effect rather than literal shapeshifting; it has been used to approach and deceive victims. Behaviorally, he is a serial killer operating under the delusion that he requires nutrients and hormones from victims' hearts to stay alive, and has cannibalistic elements to his crimes. He is most dangerous when off his prescribed medication and free from custodial restraint.