Erg was a member of the Morlocks who was able to absorb all forms of energy and project them in blasts from his left eye, which he called his "electric eye". Erg was one of the few Morlocks to survive the Marauders' attack during the 'Mutant Massacre'.
He was the first mutant to seek the Xavier Institute following M-Day, when Erg, Mammomax, and Peepers were running from the murderous Sapien League. They had the Leper Queen ordered her men to kill them now.
The League members set up three St. Andrew's crosses with braces to keep the crosses upright. Gasoline was poured on and a lit match tossed. Erg regained consciousness when the lower legs of the cross were blazing. He would have died if he hadn't been yanked off by Wolverine, who had been sitting in the Xavier estate woods, letting Colossus sketch him.
He claimed he had an uncle, unnamed, who was a Hell's Angel and that the Hell's Angels wear a 1% badge because the Media said it was just one percent of bikers who caused the trouble when a biker gang tore up a town called Hollister back in the 1940s.
He was one of a few mutants who attacked Sentinel Squad O*N*E (Office of National Emergency) because they wanted to leave the Xavier estate. Mister M ended that fight.
Erg was also accepted having an electronic tag inserted in order to be allowed to go out on a supervised group trip to Salem Center. Dr. Valerie Cooper told the mutants that the tags were "...a harmless tracking device, inserted with a simple and painless surgical process." That wasn't true, as Erg figured out too late. Later on, Mister M took the liberty of freeing the chipped mutants of their devices. Erg later appeared under the leadership of Masque.
Erg was later seen during Second Coming. He then mooved at Madripoor where the new mutant utopia was been set by Mystique's Brotherhood, leading a band of thugs and dealing Mutant Growth Hormone provided by the Brotherhood. Trying to beat up Magneto, he and his band were all taken down. It is unclear whether Erg was killed or simply wounded.
Erg has appeared in a few episodes of the X-Men: The Animated Series with his fellow Morlocks and fought the X-Men.