J. Geil is a prominent antagonist in the "JoJo's Bizarre Adventure" series, specifically in the "Stardust Crusaders" arc. He is a Stand User and the son of Enya the Hag. His Stand, Hanged Man, has the unique ability to exist within reflective surfaces, making him a formidable opponent. J. Geil is known for his cruel and sadistic nature, playing a key role in the murder of Jean Pierre Polnareff's sister, which sets Polnareff on a path of vengeance. His actions and abilities make him a significant threat to the protagonists.