Lightning struck twice in the Santos family. A Mexican-born American citizen, Carlos Santos was a misguided patriot who joined the Legion of the Living Lightning, a high-tech militia group seeking to overthrow the U.S. government, ostensibly for the good of the American people. When the Legion tried to manipulate the monstrous Hulk, he wrecked their hidden base in the Santa Ana Mountains and most of them died, including Santos. Years later, Carlos' eldest son, Miguel, resolved to redeem the memory of the Legion and his father. Locating the Legion's former base, Miguel tried to salvage their equipment and accidentally electrocuted himself. Somehow transformed into living electrical energy by the Legion's lightning machine, Miguel declared himself the Living Lightning and went on a power-crazed rampage until he was seemingly destroyed by the Avengers.

Santos was rescued by criminal scientist Doctor Demonicus, who provided Miguel with a containment suit to control his power-though he made it clear that the suit could be deactivated and Miguel's energies dispersed if Santos ever crossed him. Living Lightning served reluctantly as a member of Demonicus' Pacific Overlords criminal group while they established their island base Demonica; but in the end, Miguel rebelled against Demonicus and sided with the Avengers, who recruited him into their team.

Going home to Los Angeles for the first time since his transformation, Miguel discovered that his brother José had joined the Jaguars street gang, their sister Lisa had been killed by the rival Snakes gang, and Miguel's girlfriend Asuka had left him for Snakes leader Song. Resisting the urge for vengeance, Miguel broke up a tense confrontation between the gangs and announced he was imposing peace on the neighborhood, though he was too late to prevent one of the Jaguars from killing Song. Miguel continued to serve with the western Avengers roster until the seeming death of Iron Man caused him to rethink his priorities. Stepping down from active Avengers duty to concentrate on his college studies, Miguel would return on occasion to aid the Avengers against foes such as Ultron, Morgan Le Fay, the Triple Evil, Kang and an insane Scarlet Witch. He also served as part of the staff for the Avengers' outer space monitor station in the asteroid belt between Mars and Jupiter. Whether Miguel will work with the new Avengers remains to be seen.