Juan-Carlos was trained his entire life by his father to be the next in a long line of El Muertos, masked wrestlers who wore mystical masks that granted them power. But he never wanted to be El Muerto and refused to fight El Dorado as part of a ritual for the mask. As punishment, El Dorado attempted to kill him, But Juan-Carlos' father tried to stop him, costing him his life. However, his bravery earned Juan-Carlos ten years to train. At the end of that time, he would have to defeat and unmask a masked hero.
El Muerto wanted to battle Spider-Man and approached J. Jonah Jameson about setting up a wrestling match. During the match, Spider-Man inadvertently poisoned him with a stinger that accidentally sprung from his wrist. Spider-Man immediately took him to a hospital, where he recovered from the temporary paralysis caused by the poison.
However, his time had run out and El Dorado came to kill him. Spider-Man came to his rescue and fought him until El Muerto recovered and proved his bravery by fighting El Dorado and giving Spider-Man enough time to create a reagent that dissolves El Dorado's golden armor, leaving him vulnerable to injury. Defeated, El Dorado fled.
Powers and Abilities
El Muerto's mask grants him superhuman strength (optimally lifting 30 tons) and endurance.
He us a highly-skilled wrestler, extensively trained in both freestyle and shoot-style grappling. Fluent in Spanish, but speaks broken English.