Young Jimmy Santini was with his father in an investigation of illegal toxic waste dumping in Carlsbad Caverns National Park where his father was either shot in the back by the polluters or fell to his death in the deep caverns (the full details were murky in Jimmy's diary). Jimmy was lost in the caverns and drank water that "tasted like metal." He was eventually rescued and returned to his mother. Soon the chemicals began to take effect and Jimmy sprouted wings. His mother proclaimed him a demon, causing Jimmy to run away. He continued to mutate into a bat-like creature and ended up stealing food to survive. He arrived in New York City and made his home under an old pier. Jimmy began stealing food from people dining on rooftops scaring people in the process. Thus, the people began to dub him Batwing.