The Birth of Doomsday

The nameless being later to be called Doomsday was artificially created in the distant past on Krypton, long before the humanoid Kryptonian race had gained dominance over the planet. During this time period, Krypton was a violent, hellish world where only the absolute strongest of creatures could survive (at the time, the world's dominant lifeforms were said to be the most dangerous creatures in the universe). Doomsday's creator was a mysterious alien named Bertron, who wished to create the ultimate life-form. To do so, Bertron and his team sent a baby onto the surface of the planet, where it would be instantly killed by the harsh environment or the vicious creatures inhabiting it. Each time, whatever of the lifeform's remains that survived were harvested and used again, to create a better, stronger version than the previous. In short, the mad scientist was using the method of cloning to accelerate the evolution of the being he was creating. Through decades of this process, the being who would eventually become Doomsday was forced to endure the agony of death, thousands upon thousands of times; the memory of these countless deaths was recorded in his genes and drove it to hate all life. Eventually, Doomsday gained the ability to evolve against what killed him in his prior life without the need of Bertron's technology. At this point he proceeded to hunt down and kill all of the lethal creatures that inhabited Krypton. Bertron himself met his death at the hands of his own creation.

Doomsday and Superman

In his first encounter with the Justice League, shortly after breaking free from underground, Doomsday defeated the entire team of superheroes in a matter of minutes, which in turn attracted the attention of Superman. During his rampage, Doomsday took interest in billboards and television spots advertising violent wrestling competitions held in Metropolis, which appealed to his bloodlust and thus enticed the otherwise mindless creature to head towards the city. By counterattacking, Superman quickly found that his opponent's awesome power was a match for his own, and so he realized that if Doomsday actually reached Metropolis, the resulting battle could conceivably destroy the city and kill millions of innocent people. Doomsday battled Superman in a titanic struggle, leading the hero to conclude that the creature would only continue to attack relentlessly and endlessly, with no urge for surrender. In an act of self-sacrifice, Superman refused to give up despite taking serious wounds and running low on stamina. The fight raged to the bitter end, where the two combatants each struck a simultaneous, fatal blow, leaving both of them lifeless in front of the Daily Planet building in Metropolis.

Doomsday's Superpowers

Evolutionary Regenerative Healing Factor: Doomsday was created and evolved through cloning an infant and having it killed over and over again by one of the most dangerous species of the universe and in one of the harshest habitats in existence, prehistoric Krypton. As such, he returns to life every time he dies and becomes resistant or immune to what killed him before.

Adaptive Resistances: Doomsday can also develop/evolve resistances to whatever injures or harms him.

Bone Protrusions: As a result of these evolutions, Doomsday is covered by bony protrusions all through out his body that serves as added protection and as weapons.

Superhuman Strength: Doomsday is able to easily lift in excess of 100 tons ;Doomsday possesses vast super strength; even more than Superman.

information from dc.wikia.com