Thousands of years ago, a long-since forgotten civilization worshiped their demon-god Nebiros. Their priests breached the void between his dimension and our own, unleashing the monster on the world. They sacrificed captives to him, and in return he led their armies in an attempt to conquer the world.
Eventually Nebiros' empire grew to threaten the other great powers of the day: Mu, Lemuria, and Atlantis. The greatest mages of these realms branded together to defeat Nebiros. They vanquished his armies and banished him to his own dark dimension; forever they hoped.
But six thousand years later, Nebiros possesses the body of the Swamp Thing with the aid of a deluded priest Jonathan Bliss. Abigail Arcane and Matthew Cable destroy the globe vessel. Nebiros is exorcised from the Swamp Thing and enters the body of the priest, withering under the priest's spirit Nebiros is vanquished back to his realm. He was accidentally freed by Sharon Scott and Wayne Tarrant, friends of Dan Cassidy, during the filming of Blue Devil. Cassidy defeated the monster, returning him to his realm, but at a terrible cost to himself.
Shortly thereafter, Nebiros became freed again, this time threatening Mexico. Once more he was defeated by Blue Devil with the help of Zatanna.
Now Nebiros broods in his dark realm, dreaming of returning to Earth to conquer the world and gain revenge on Blue Devil.
The Demon Etrigan and the fallen demon Asmodel battle had caused Asmodel to merge with the Spectre. The fires of Hell going out were one of the side effects. The Demons then fled to Earth with the fires gone out. A small band of heroes led by Faust went to Hell to restart them. All the demons invaded Earth except Nebiros, who claimed to be armed with the trident formerly owned by the King of Lies. Faust, using bones he bought in Paris, brings Blue Devil back to the living. Blue Devil steals back the trident, kicking him high in the air. Firestorm than blasts Nebiros turning the water in his body to cement, seemingly killing hm.
Nebiros was summoned by Tobias Whale, using the Demon Chalice which was thought to be just a movie prop. He then proceeded to feast upon the souls of Tobias's men, including his female assistant, who he did offer a greeting to before consuming her. Before he could do the same to Tobias, the drug dealer showed him a picture of Blue Devil, who Nebiros recognized, and offered him a deal. Nebiros wanted Blue Devil and Whale wanted power.
Nebiros used his magic to create a new drug for Whale, one that caused those who took it to explode or become mindless shells which they could control. One of the victims was a friend of Eddie Bloomberg, Daniel's godson. They took Black Lightning's father hostage, drawing the two heroes to them where Nebiros sought to reclaim his skin, Blue Devil's suit, after it had been cut off of him centuries ago by Etrigan the Demon. Largely due to the effects of trivializing it by Blue Devil's family, the skin rejects him, which angers him further.
When Tobias Whale shoots Black Lightning, Blue Devil strikes a deal with Nebiros to save his life, but then betrays the demon and traps him inside Whale's body, leaving him in the comatose form even when it's shipped to a prison. It is unknown what side effects Blue Devil will encounter because of the deal and because of his betrayal to Nebiros.