During location filming on the mysterious Ile Du Diable, Wayne Tarrant, the "hero" of the film, and his co-star (and Dan Cassidy's eventual girlfriend) Sharon Scott, accidentally freed a demon named Nebiros. Though Cassidy faced incredible odds and a near-death experience, he was able to effectively use the devices built into his costume to drive the demon back to its home dimension. Unfortunately, he was blasted with demonic energy in the process. After the fight, Cassidy found that the blast had permanently grafted the Blue Devil costume to his body. Cassidy, a devout Irish Catholic, was stuck in the "skin" of an unholy Blue Devil.