There are several Spanish Conquistadors who survived to the modern era via the effects of the Fountain of Youth. Four of them were sent out to capture the Man-Thing and perished, either in the conflict, or from the stress of doing so. At least three other Conquistadors have been seen, all of whom tried and failed to drive the Man-Thing from the village when he first entered la Hacienda. Alejandro and Diego were among the first four who died.
The current hero known as the Conquistador was a 14th Century explorer who discovered the Fountain of Youth and could live forever, permanently altering his physiology as he no longer had blood in his veins, but something else entirely that gave him immortality. The magical water has filled his body, protecting him from age and sickness.
At some point the Conquistador signed on under the 50-State Initiative to join as a superhero. He was assigned to the Florida state team known as The Command where they were sent to investigate the reporting of odd behaviors in a Florida swamp.
While on the mission to the Florida swamplands, they were attacked by zombies from another reality. He fought valiantly, but while they could not eat him or infect him, they managed to tear him apart.