In the distant past, a dying alien race created a number of devices to preserve their culture, and sent them into space, where they would encounter other civilization and link their colonies. When a small group of these aliens arrived on Krypton, a militaristic faction, led by Kem-L, killed them and corrupted one of their devices to preserve his ideal of Kryptonian culture; the device would eradicate alien influences, and hence he called it the "Eradicator."

One of the surviving aliens, The Cleric, took the Eradicator and a group of followers and left Krypton. Unfortunately, his followers died shortly after leaving; Kryptonians have a genetic link to their planet, and will die if they leave it.

The Cleric's dying act was to deliver the Eradicator to earth where he learned of a surviving Kryptonian. He however died before he could find Kal-El and the Eradicator was discovered by Steel because of it's attempt to turn Earth into a New Krypton.

Once John discovered the devices porpoise he reprogrammed it to use it's Kryptonian technology to protect Earth. It then drew power from the sun and fueled a transformation into an energy being that then merged with a scientist working the project to clone Superman, David Connor. Some of the DNA used in the cloning attempts was caught in the merger and the Eradicator became a Human/Kryptonian Hybrid. Though he has the typical Kryptonian powers he has super strength, flight, energy projection, invulnerability, but also gained enhanced senses, and computer-like analytical ability. He however had none of the vision base like heat vision or x-ray vision. In his new form he is a force to be reckoned with and his loyalty to the Rebellion knows no bounds.