Little is known about the background of Antonio Rodriguez other than that he has a criminal record and wife named Maria. His wife critically stricken with an undiagnosed disease, Rodriguez took her to every doctor who would see her but none were able to determine the nature of her illness, let alone help her. In desperation, he sought Dr. Karl Malus, a criminal scientist who specializes in the generation and bestowal of superhuman powers, whom he had heard about while in prison. Malus agreed to try to cure her in exchange for the man agreeing to become his test subject and employee for an indefinite period of time.
Malus had long been interested in acquiring a superhuman henchman, particularly after his experiments on the Fly, the Hornet, the Werewolf, and Goliath failed to provide him one. Malus subjected the man to an experimental process that combined genetic material from an armadillo with the man's genes. The Process caused the man's strength to increase drastically, his skin to transform into a tough, organic armored plate, and his hands to grow thick tough claws. Malus dubbed him the Armadillo and assigned him to break into the West Coast Avengers Compound to steal the comatose body of Goliath who was being held there. The Armadillo complied and soon found himself in combat with visiting Captain America. Although physically superior to him, the Armadillo was defeated by the Captain's superior combat skills. Taking compassion on the Armadillo's plight because of his wife's condition, Captain America refused to turn the Armadillo over to the authorities. After Malus cured Maria, Armadillo joined the Unlimited Class Wrestling Federation.
Armadillo escaped from the raft after Electro's break out. Recaptured by the New Warriors he was later placed in the fifty states Initiative as part of the Texas Rangers. Later attending Stilt-Man’s wake, it is unlikely that Antonio was hurt by the attack carried out by the Punisher due to his thick hide and altered genetics.