Overview
Blue Devil (Daniel Cassidy) is a superhero appearing in American comic books published by DC Comics. He first appeared in a special insert published in Fury of Firestorm #24 (June 1984). That story led directly into Blue Devil #1, also cover dated June 1984. He was created by Dan Mishkin, Gary Cohn, and Paris Cullins. The Blue Devil comic book ran for 31 issues and one annual. Blue Devil later appeared as a regular character in Shadowpact which ran for 25 issues.
Dan Cassidy was working as a stuntman and special effects specialist in Hollywood when he created the Blue Devil suit, complete with a built-in exoskeleton, specifically designed for the production of a Blue Devil movie. During filming, the demon Nebiros was unleashed from within an ancient temple and, thinking Cassidy was an actual demon, tried to drain his demonic powers with blasts of magic. Instead, the blasts permanently bonded the suit to Cassidy. This unnatural fusion of magic and technology caused him to experience unusual events and draw the attention of otherworldly beings. Horrified at the prospect of being stuck in the suit forever, Cassidy sought ways to separate himself from it, becoming a reluctant superhero along the way.
Cassidy was eventually transformed into an actual demon after making a deal with the demon Neron. Regretting the deal, Blue Devil decided to fight occult evil, often alongside the other members of Shadowpact.
Cassidy's original trident was a mechanical device that he designed himself, but, after being turned into an actual demon, he acquired the magical "Trident of Lucifer" to help combat demons.
From Wikipedia (CC BY-SA 4.0).