Neron is a Devil. He generally offers deals to villains and heroes usually for their souls. Neron has no limits in power and apparently cannot be defeated.
In Underworld Unleashed, the first appearance of Neron, he recruits villains and heroes to join him and do what he says. For following him some of them don't have to lose there souls to gain there power. Neron however is defeated when Trickster comes out and helps the heroes know that he cannot take a pure soul who sacrifices himself which is what Captain Marvel does. In the series, many villains sold their soul. One of which was Joker who sold his soul for a box of Cigars.
Another character who "sold" their soul to Neron was Lobo, during the time of Underworld Unleashed. After taking the soul of Doc Bugg (aka "The Bugmeister") and granting him insect powers in return, he propositioned Lobo, who agreed to sell his soul. After Neron took his soul and agreed to grant Lobo with anything he desired, Lobo demanded Neron's soul as payment. Not having a soul of his own, Neron offered Lobo his soul back and asked if there was anything else he could offer as compensation for their misunderstanding.
Earlier that day, Lobo's neuro-transmitter, which was tuned into Cosmic Rock Zombie Radio 24/7, had changed DJ's and was playing nothing but soul music, and Lobo made the request that the neuro-transmitter be placed in Neron's brain instead, and he also said that Neron could even keep his soul. As Neron walks away, we see the soul music playing from his forehead, leaving Neron apparently discontent. Whether or not he still has the transmitter in his brain has not been addressed since.
He also killed Wonder Woman for a time, but she was restored by her gods.
Neron next appearance is when Ralph Dibny summons him to the Tower of Fate demanding that he do as he demands for bringing Felix Faust. He denies and then goes on to kill Ralph only to find out they are trapped until Ralph is awoken and speaks to them.
One Year Later
In Black Adam The Dark Age is revealed that Neron somehow found a way to escape Dr. Fate's tower, though the means currently remains unknown. Neron appears in Teen Titans and is the reason for Kid Devil's new look and powers. Neron will come back for his soul in two years after he loses faith in Blue Devil. When Eddie realizes Blue Devil accidentally caused the death of his aunt he loses faith. In Birds of Prey, Black Alice copied his powers and brought back her mother.
Reign in Hell
Neron is currently engrossed with the goings on in his own realm. When Lord Satanus and his sister Blaze, bastard children of the late wizard Shazam and a demoness, gained control of Purgatory, they began a campaign to control all of Hell. Using the slogan of "Hope for the hopeless" they have managed to rally many to their banner. Neron is preparing to unleash the full furies of his armies and power upon them in defense of his throne. Eventually, he gets into a one-on-one fight with Satanus. Satanus uses a spell to turn all the demons in hell into humans, draining Neron's power, then beheads Neron.
Powers and Abilities
Neron's Powers are all on God like levels making him one of the most Powerful Devils in the DCU.
Aura of Fear
Hell Realm: It should be noted that inside his own realm, Neron’s powers grow exponentially, even to cosmic levels
At one point in his life, Neron was demoted in rank and thrown in with the caste of rhyming demons.
Candle of Neron: Soul Jar