
It began 245,000 years ago on Bylan 5, where Darkseid was about to wed a princess (in order to obtain that planet's chemical deposits for Apokolips' weapons factories). The Ultimate escaped Krypton via a ship that regularly came to deliver supplies to Bertron - who wanted little contact with the planet's natives - and went on a killing spree across several planets.

He then killed Bertron himself, whom he had come to identify as an enemy, due to Bertron having "killed" him thousands upon thousands of times. "The Ultimate" hunted and exterminated the dangerous predators of Krypton. Eventually, he gained the ability to thrive on solar energy without the need for food or air, to return to life and adapt to overcome whatever had previously killed him, without the assistance of Bertron's technology. Evolving, the child later became able to survive the high temperatures and searing atmosphere, only to be quickly slain by the vicious predators that inhabited the planet. The agony of these repeated deaths was recorded in his genes, driving the creature to hate all life.

The baby's remains were collected and used to clone a stronger version, a process repeated time after time as a form of accelerated artificial breeding. In a cruel experiment intended to create the perfect living being, the alien scientist Bertron decanted a humanoid infant (born in a lab in vitro) onto the surface of the planet - where he was promptly killed by the harsh environment. It was a violent, hellish world where only the absolute strongest of creatures could survive. Originally known as The Ultimate, he was born in prehistoric times on Krypton, long before the humanoid Kryptonian race had gained dominance over the planet about 250,000 years ago. He is a nearly mindless, berserk killing machine, with no feelings apart from unfocused hatred, murderous rage, and the sheer malicious joy of destruction.

Doomsday is best known as Superman's murderer in the 1992 storyline, " The Death of Superman".
