"If Man won't kill God, the Devil will do it! Ancient, Kryptonian deformity! Blood of my blood! Born to destroy you! Your Doomsday! And now God... is good... as dead!"
Doomsday was a bloodthirsty mutated Kryptonian, created by Lex Luthor from the corpse of General Zod (combined with his own blood, in a long-forbidden ancient ritual), in order to bring down both Batman and Superman. Not only is he capable of apocalyptic levels of destruction, carnage, and death, but his immense physical might was far greater than the combined forces of Wonder Woman, Superman and Batman themselves. He was, however, ultimately killed by the Man of Steel, though a dying Doomsday seemingly killed him as well.
In order to ensure the success of his final goal of killing Superman (if Batman were to fail), Lex Luthor enters the Fortress of Solitude (by finally using the fingerprints of General Zod and re-inserting the command key), assumes command, and orders to be taught all of the knowledge from 100,000 alien worlds that the starship's archive contains (which enhances Lex's already brilliant intellect to supergenius level).
Among the tremendous amount of new knowledge Lex gains, he learns of an ancient Kryptonian monster, and promptly decides to re-create it, as a final contingency plan.
In order to begin the lengthy process, Lex brings in General Zod's corpse (lamenting that the alien invader had "[flown] too close to the sun") into the genesis Chamber, cuts his own palm, and pours his own blood onto Zod's face. The starship warns Lex that re-creating the fearsome monster was forbidden by the Kryptonian Law Council, but Lex notes that the council is long-gone along with its destroyed planet, and orders the process to commence.
Birth
While the process is still going on, Lex has Anatoli Knyazev kidnap Martha Kent, and then confronts Superman, presenting him with a horrible ultimatum, in order to force the alien superhero into a mortal duel with the equipped Batman. However, this plan ultimately fails, and Superman flies to the Fortress of Solitude to confront Lex. However, mere seconds after Superman comes crashing through the starship's building (while Batman simultaneously saves Martha from Knyazev's men), the birthing process is complete, and Lex gleefully proclaims the monster to be "Superman's Doomsday", just as the massive monster smashes his way out of the Genesis Chamber's birthing martix. Lex gleefully added that now Superman was "as good as dead."
Superman catches Doomsday's punch.
Doomsday unleashes a thunderous roar, and hurls a monstrous punch at Lex. However, the punch is intercepted by Superman, who blocks and counters with a blow of his own. The battling duo then proceed to break out of the Fortress, continuing their mortal duel.
Battle with the Trinity
Doomsday breaks free of the Fortress of Solitude and leaps into Heroes Park. Superman pursues Doomsday, and the two do battle, Doomsday destroying the Superman Statue in the process. Doomsday's strength surpasses Superman's, but he manages to hold his own and sends the creature flying into a building. Subsequently, Doomsday is fired at by military helicopters, but is not harmed. He adapts to the fire and only becomes more durable.
Doomsday and Superman face off at Heroes Park.
Doomsday is then launched into space by Superman. The US President then sends an order to shoot Doomsday down with a megaton nuke, carried out by General Swanwick. Seeing the missile approach, Superman defiantly holds Doomsday still, determined to destroy the beast. The warhead hits with an explosion so gigantic, that it can clearly be seen from Earth's surface.
Falling back to Earth, Doomsday's body lands on Stryker's Island, but is far from dead. The explosion seemingly only making the creature stronger. Doomsday's body once again regenerates. Recovered himself, Superman then charges at Doomsday yet again, sending the beast flying where it collides with a chemical silo. Batman attempts to distract Doomsday, but is eventually cornered. Doomsday shoots his heat vision at him, however the rays are deflected by Wonder Woman.
Superman and Wonder Woman then proceed to attack Doomsday in tandem, while Batman tries to expose the monster to the Kryptonite gas. Superman then leaves to save Lois Lane from drowning and retrieves Batman's Kryptonite spear. Batman is successful in exploiting Doomsday's only known vulnerability. Seeing her chance, Wonder Woman attacks and manages to cut off the creature's arm with the Sword of Athena. However, it only results in a tremendously sharp skeletal protrusion growing back in its place.
Last Stand and Death
Wonder Woman manages to temporarily restrain Doomsday with her lasso. Superman sees that the only way to stop Doomsday is to risk his own life. He charges at the creature, exposed to the Kryptonite himself, and stabs Doomsday in the chest with the Kryptonite Spear. However, the spear did not manage to fully pierce Doomsday and he is able to stab Superman in return, piercing his chest with the bone protrusion on his arm. A mortally wounded Superman is undeterred by his impending death, and he uses his last reserves of strength to further impale Doomsday and manages to fully push it through the other side, finally killing the monster, though himself dying in the process. With a final bellow of agony, the now lifeless bodies of hero and monster collapse upon the ground. What became of Doomsday's corpse, remains unknown.
Personality
"A deformity so hateful to sight and memory - the Desecration Without Name!"
Doomsday is an extremely ferocious monstrous being with an insatiable bloodlust, desire for destruction, and carnage, which makes him a nearly unstoppable threat of apocalyptic proportions. However, due to Doomsday's feral mind, he therefore has a limited intelligence, being unable to tell the difference between friend and foe, attempting to kill his creator Lex Luthor right after emerging from the Genesis Chamber, and he thus owes allegiance to no one but himself. Therefore, while incredibly dangerous, Doomsday was relatively quickly outsmarted by Batman, who baited the monster into following him, which allowed Wonder Woman to get a hold of Doomsday with her lasso, which allowed Batman to momentarily weaken the monster with a Kryptonite gas grenade, which, in turn, gave Superman the opening he needed to deliver the killing blow to Doomsday, with the Kryptonite spear. However, Doomsday's incredible bloodlust allowed the monster to seemingly murder Superman as well, just as he was dying.
Mutated Kryptonian Physiology: Doomsday, due to being the genetic amalgamation of General Zod (from his corpse) and Lex Luthor (from his blood), is a terrifyingly powerful being, of potentially apocalyptic proportions, thereby being the only known being to surpass the power and might of Superman himself, with Steppenwolf and Darkseid being the only known other beings to rival Doomsday's might. Thus, Lex Luthor creates him for the sole purpose to killing Superman, naming the monster "[Superman's] Doomsday", and claiming that Superman was "as good as dead" if he were to fight Doomsday. Indeed, the monstrous juggernaut's unparalleled might forced Superman to team up against it with Wonder Woman and Batman in order to stand a chance, yet even that was insufficient, as Doomsday's ability to "evolve" and regenerate at a rapid pace made him impossible to be brought down with brute force alone, so while Superman managed to ultimately bring him down (with a Kryptonite Spear), he only succeeded by seemingly dying himself in the process.
Super Strength: Doomsday has a tremendous level of superhuman strength, virtually incalculable, somewhat superior even to that of Superman (making him the only known being to be stronger than him), forcing the Man of Steel to team up with both Batman and Wonder Woman in order to stand a chance against the monstrous juggernaut. Thus, Doomsday is strong enough to generate large shock-waves with his monstrous blows, to hold his own against the combined tremendous might of both Superman and Wonder Woman simultaneously, sending them flying with his blows, and to actually harm Superman without the need of Kryptonite, managing to swiftly pierce the latter's otherwise invulnerable chest with his tremendously hard and sharp bony protrusions.
Super Leaps: Doomsday is able to use his incredible strength to perform super jumps, shown when he leaped from the ground in Heroes Park right onto the spire of LexCorp Tower, in a single bound, destroying multiple helicopters in the process.
Super Speed: Doomsday, while not quite as fast as Superman, can, like Wonder Woman, move at considerable superhuman speeds, with Batman just barely managing to grapple away from the charging monster.
Super Stamina: Doomsday has incredible, virtually inexhaustible stamina, never needing to stop during his prolonged intense battle with the superhero trinity.
Invulnerability: Doomsday is virtually invulnerable, even more so than Superman. Thus, the monster was unscathed by the intense firepower of military jets and the Batwing, numerous tremendous blows from Superman and Wonder Woman, and even quickly recovered after taking the full force of a megaton nuke (in an explosion in outer space, gigantic enough to be seen clearly from Earth), and subsequently falling down all the way down to Earth from space. Due to his adaptive evolution, the megaton nuclear blast, fall, and mighty blows from Superman and Wonder Woman actually only made Doomsday stronger and more durable than before. The only known weapons capable of actually injuring Doomsday are Wonder Woman's Godkiller sword (due to the sword's magical nature) and weapons containing Kryptonite (due to the monster sharing Kryptonians' weakness to the xenomineral).
Bone Protrusions: Doomsday's bony protrusions are virtually indestructible and tremendously sharp, to the point that the monster was able to use his arm-protrusion to stab right through the otherwise invulnerable chest of Superman, which seemingly mortally wounded him.
Healing Factor: Doomsday has an extremely effective healing factor, making him incredibly hard to defeat, even for the most powerful of opponents. Hence, when somewhat injured by Superman's blows, a megaton nuke, and his subsequent fall from space, Doomsday recovers and heals almost instantly, and grows a huge bony protrusion right after his arm is chopped off by Wonder Woman. Whenever injured, Doomsday's healing wounds are instantly enveloped in an orange superheated glow, which vanishes after he is healed, mere seconds later.
Regenerative Evolution: Upon receiving catastrophic injuries from the missile, he not only regenerated, but his body started to mutate further, possibly as a adaptive response to the trauma. Thus, the more Batman, Wonder Woman, and Superman attack Doomsday, the stronger and more durable the monster became, also growing in size, making Superman realize that wielding the Kryptonite Spear is the only way to stop Doomsday.
Energy Absorption: Doomsday's cells, like those of any Kryptonian, are capable of absorbing multiple kinds of energy, for both sustenance and enhancement, with Wonder Woman remarking that the monster feeds on it. Having absorbed a considerable amount of energy, Doomsday is induced to mutate and increase in power, with him notably growing bony protrusions and growing in size after surviving a gigantic megaton nuclear blast and absorbing the nuclear energy of it, along with the kinetic energy of his colossally high fall from outer space. Doomsday also absorbs the tremendous kinetic energy from Superman and Wonder Woman's mighty blows, with their hits therefore only making him stronger and more powerful.
Electrokinesis:
Doomsday produces electricity.
Doomsday, when healing from a powerful attack, is capable of generating immense electrical tendrils and shock-waves from his body, with Doomsday generating a larger and more powerful shock-wave as he increases in power. One of them was powerful enough to decimate several city blocks, tearing apart many buildings, with only beings of tremendous power, like Superman and Wonder Woman able to survive the electrical shock-wave head-on (with Batman and Lois Lane narrowly escaping by hiding behind some rubble and underwater respectively). When mortally wounded, Doomsday used his electrical tendrils to loosen the hold of Wonder Woman's unbreakable Lasso of Truth (by making her temporarily lose her footing), thereby managing to mortally stab Superman.
Doomsday can generate tremendous superheated torrents from his eyes and mouth, which are far larger and more destructive than even Kryptonian heat vision, with a single thermal blast being enough to completely destroy a building's entire floor. Only beings of tremendous power, like Superman and Wonder Woman can survive a thermal blast from Doomsday head-on. Hence, when Superman tried meeting Doomsday's blast with his heat vision, the monster's much thicker beam was able to overpower Superman's relatively quickly, promptly sending Superman flying backwards.
Kryptonite: Doomsday, much like Superman and other Kryptonians, has Kryptonite as his main weakness, with this radioactive green xenomineral being extremely toxic to him, making it the only known substance capable of actually killing the monster. Hence, Doomsday is considerably slowed down when Batman shoots him with a grenade of Kryptonite-rich gas, and killed when Superman stabs him through the chest with a Kryptonite spear, with the mortally wounded monster roaring from the incredible pain.
Beings of Equal Power: Doomsday can be effectively engaged in combat by beings of comparable incalculable strength, such as Superman, Wonder Woman, New Gods, or Olympian Gods, with Superman and Wonder Woman's their tremendously mighty blows being capable of staggering him, and, in Superman's case, even sending Doomsday flying. However, his adaptive evolution and healing factor makes the monster incredibly hard to kill, even for them.
Magic: Doomsday shares Kryptonians' vulnerability to magic, with allows Wonder Woman to both chop off his arm with the Godkiller, and restrain him with her magical Lasso of Truth, with him unable to absorb its magical energy and break out of the noose. He was, however, able to grow a huge bony protrusion in the arm's place, and to slightly loosen the lasso's hold on him with an immense electrical blast of his own, as it made Wonder Woman momentarily loose her footing.
Limited Intelligence: Doomsday, as a ferocious being with an insatiable bloodlust and desire for destruction and carnage, has a feral mind with limited intelligence, which was ultimately his downfall, as it allowed the superhero trinity to ultimately outsmart Doomsday, with Batman baiting it, which allowed Wonder Woman to get a hold of him with her lasso, which allowed Batman to momentarily weaken the monster with a Kryptonite gas grenade, which, in turn, gave Superman the opening he needed to deliver the killing blow to Doomsday, with the Kryptonite spear.
