Daniel Cassidy is a
special effects wizard and
stuntman hired to create and play the title character in the movie
Blue Devil, leading him to create a full-body costume with a hidden powered
exoskeleton and built-in special-effects devices. When two of his co-stars accidentally free a demon named
Nebiros, Cassidy uses his costume's abilities to drive the demon back, but is blasted by mystical energy. After the fight, Cassidy discovers that the blast grafted the Blue Devil costume to his body. Cassidy quickly finds himself embroiled in adventures and conflicts with
supervillains, as his newfound status has turned him into a "weirdness magnet". After failing to find a way to remove his costume, Cassidy starts to enjoy his new lifestyle, and becomes more comfortable as a superhero, even accepting a place in the
Justice League of America. He gains a sidekick when Eddie Bloomberg, his former gofer and devoted fan, designs a suit similar to his own and becomes
Kid Devil. Eventually, he moves into "The House of Weirdness" with
Cain as his superintendent.
Blue Demon and later alliances During the
Underworld Unleashed storyline, Blue Devil is approached by the demon
Neron, who is known for offering
Faustian bargains to heroes and villains alike. Neron offers Cassidy, who is increasingly bored with superheroics, the chance to finally be the famous actor he had always wanted to be. As payment, Neron sends Cassidy to destroy an unmanned
electrical substation in the desert. Believing it to be a relatively harmless act, having checked that nobody was working that night and a relay station would kick in to carry the load, Blue Devil complies and inadvertently causes the death of Marla Bloom, Eddie Bloomberg's aunt, as the resulting power outage causes a crash that kills her. The story of his personal loss is enough to attract several movie offers. Blaming Neron for Marla's death, Cassidy foils the demon's short-term plans but dies in the process. Cassidy is quickly revived, but this time as a true demon, and is unable to set foot on consecrated ground without bursting into flame. Blue Devil joins the Justice League again, until his second death at the hands of
Mist, who showers him with
holy water. Blue Devil is resurrected again by
Sebastian Faust, who hopes to gain his assistance restarting the fires of
Hell during the
Day of Judgment storyline. Blue Devil has a chance to confront Nebiros, empowered by a magic trident seemingly given by the King of Lies himself. Blue Devil stalls Nebiros, stripping him of his trident and allowing
Firestorm to deal the killing blow; back on Earth, the other heroes of the
Sentinels of Magic save the world. Blue Devil joins the Sentinels of Magic and begins an uneasy partnership with Faust. Faust restores Blue Devil's freedom by restoring his last missing bone. Blue Devil sacrifices his life fighting
Hermes Trismegistus, but as a true devil he returns to life again. He is tasked to roam the Earth with Lucifer's Trident, sending escaped demons back to Hell.
One Year Later One Year Later, Blue Devil is employed as a bouncer at the
Oblivion Bar, an interdimensional place for magical beings, and there he is recruited by
Ragman,
Enchantress, and
Detective Chimp to battle the
Spectre in
Day of Vengeance. With his enhanced demonic strength, he is the heavy hitter of
Shadowpact, the assemblage of magical heroes devoted to fight for every "lost cause". This grouping is even able to wound the powerful
Eclipso. Feeling necessary for the first time in a long time, he devotes himself to the team. One of their goals is to help look over the wild magic of the "Tenth Age", a direct result of the events of
Day of Vengeance. His demotion is explained as the paradoxical condition of his being both a hero and a demon: being famous and loved by everyone, he makes Hell a glamorous place, spurring weak minds to attain his glamour by selling their souls to Hell. Zauriel, on behalf of his good faith, takes Blue Devil's place in Shadowpact, giving him enough time to get out of his infernal deal. Blue Devil puts his case in the hands of an eager lawyer, more than happy to be able to confront Hell itself in a hall of justice. Blue Devil undertakes the task of completing 13 labors, as
Hercules before him, on behalf of the
Catholic Church as a show of good will. Returning to Hell for the final hearing, he discovers that Jack of Fire was the one selling his sibling's soul first, with Blue Devil merely following unwillingly. His lawyer repeatedly proves that Jack is the only one who can return Cassidy's soul, and the souls of his family, back, since he was the one who sold them in the first place. Blue Devil uses his new lower status as a Rhyming Demon to force Jack to do so, but in the process he loses both Lucifer's Trident and his demon form, reverting into a mortal. Jack of Fire is now allied with a seemingly all-powerful Sun God, but plots to betray him in retaliation for his harsh treatment and to lead an army of demons on Earth. Cassidy feels forced to don a new suit of armor, very similar to the one he wore during his Hollywood years, but even more powerful. He sets off to fight his brother, who refuses. Instead, after a brief confrontation, acknowledging that the Sun God will eventually kill him for his betrayal, he commits suicide in front of Cassidy, naming him inheritor of all his powers and demonic status - but without forfeiting his soul. Cassidy rejoins Shadowpact to defeat the Sun God, and Zauriel ends his temporary membership with the group. During the
Reign in Hell storyline, Cassidy convinces
Zatanna and
Sargon the Sorcerer to take him to Hell and accompany him as to make a deal with Lord Satanus against Neron; when, after much suffering, they reach Satanus, he pleads to be incorporated into Satanus' attack force in hopes of receiving the gift of full humanity from the demon in case of his victory. Inadvertently, he brags about being capable of handling
Etrigan, who is causing damage to Satanus' forces; Satanus takes heed of this and teleports him to do battle with Etrigan. Upon losing, Etrigan steals the remains of his humanity. Later, due to the effects of the magical drug Satanus has released all over Hell, he is transformed into a human, but soulless. Etrigan offers him his soul back, warning him the drug only worked on pureblood demons such as the type he had been transformed into when Etrigan stole his soul, meaning accepting it back meant permanently returning to his demon form. He is later traumatized by Sargon's sacrifice to let almost all heroes intervening in the War of Hell escape to
Nanda Parbat and is later the only one convinced of reuniting Shadowpact by Detective Chimp. He appears with Zatanna and the
Phantom Stranger at the desecrated grave of
Batman.
Black Lantern rings take control of
Crispus Allen. While Zatanna is sent to gather the Justice League, Blue Devil and the Stranger attempt to stop the Black Lantern Spectre, failing miserably. He and the Stranger head to Nanda Parbat, where the Stranger helps
Deadman remove the black ring from his body. The Phantom Stranger tasks Blue Devil with protecting the body, being told that it is of "singular importance".
The New 52 In
The New 52 rebooted DC's continuity, Blue Devil is reintroduced when he breaks up a drug deal and runs into
Black Lightning, who is also there to bust the deal. They both state that they are trying to take down crime lord
Tobias Whale, but Black Lightning does not believe Blue Devil. A fight ensues, but Blue Devil quickly gets the better of Black Lightning and tries to make him listen, when he is interrupted by the
LAPD, who are ready to open fire. Black Lightning takes that opportunity to run off and Blue Devil manages to escape as well. During the
Forever Evil storyline, Blue Devil is among the magic users who are captured by
Felix Faust and
Nick Necro to use them as part of a weapon that would defeat the
creature that destroyed the
Crime Syndicate's Earth. ==Powers and abilities==