Doomsday first appeared on Earth trapped miles beneath the surface of the planet in a metal prison wrapped in chains. When Doomsday freed one hand from his chains he beat his way through steel and stone to get to the surface and see the first rays of light in countless years. A fitting contrast for the darkest creature to ever set foot on our planet or any other. Its unknown exactly how he got to Earth imprisoned in his cell but countless planets and cultures across the universe have vanished after a visit from Doomsday.
Doomsday was created by a Kryptonian scientist looking to create a creature that could survive under any circumstance. Time and again this scientist would grow Doomsday in a test tube and launch his into the most inhospitable environment he could find. Filled with ravenous creatures and a toxic atmosphere. Every time Doomsday was killed or defeated the Kryptonian would collect what was left of him and grow him again. Each time Doomsday’s gene’s would remember and evolve. Eventually Doomsday killed everything on the planet including the Kryptonian. Now every time Doomsday see’s something living all he see’s is the Krptonian that killed him over and over again.
As Doomsday traveled from world to world he fought armies, heroes and villains. The rare times that he was defeated Doomsday would regenerate stronger, deadlier and immune to whatever person or weapon defeated him before. The only real option for any world unlucky enough to have a visit from Doomsday was to capture or trick him long enough to get him off the planet and make him someone else’s problem.
When Doomsday escaped his prison on Earth he became our problem. Defeating Booster Gold, The Justice League and Supergirl before Superman put himself in the path of this unstoppable killing machine. Doomsday was killing everything as he leapt towards Metropolis city. Swat, military and our planets most advanced weapons blazed away at Doomsday while Superman put himself in the line of fire taking as much punishment as Doomsday.
Superman gave everything he had to stop Doomsday sacrificing his own life to end Doomsday. There blows were so powerful they shattered windows every time they struck each other. As they both laid dead in the streets Superman would be given a heroes funeral as the savior of Earth. Doomsday body would be locked away in an underground bunker to be studied and experimented on with no one knowing that he would regenerate. Luckily a cyborg version of Superman would later take his body to outer space and imprison him on an asteroid.
Doomsday continued to ravage the universe until he was taken to the one place that could finally put an end to his reign of destruction. A time traveler took him to the end of time were their was nothing and know one left to kill.