Doomsday is the primary antagonist of the DC animated film The Death of Superman. This extraterrestrial monster is carried to Earth on an asteroid where it goes on a killing spree, ruthlessly slaughtering anyone and anything that stands in its way.
While its comic book incarnation is Kryptonian in origin, that is not the case for this incarnation. It is revealed in Reign of the Supermen, the direct sequel to The Death of Superman, that Doomsday was biologically engineered on Apokolips. Darkseid had Doomsday bred into the perfect killing machine and sent him to Earth for the express purpose of killing Superman, eliminating Earth's greatest champion and leaving the planet relatively defenceless against Apokoliptian invasion.
History[]
Doomsday is delivered to Earth via a Boom Tube, carried upon an asteroid. The asteroid falls to Earth, plunging into the Atlantic Ocean where it is investigated by both Atlantean scouts and scientists from LexCorp. The creature, contained inside a strange suit, emerges from the asteroid and quickly slaughters both the Atlanteans and LexCorp crew before making its way to shore.
The monster reaches shore and begins carving a path of death and destruction as it heads toward the nearest population centre. Arriving in the town of Calvin Heights, it goes on a killing spree and the police are powerless to stop it. Though the Justice League intervene, even they prove to be no match for it as the Flash, Green Lantern and Hawkman are quickly defeated. Batman, despite having no powers, lasts longer against Doomsday, but ultimately nothing in his arsenal is capable of putting the monster down.
Doomsday eventually reaches Metropolis where Aquaman and Wonder Woman try to keep it at bay until Superman can join the fight. The Man of Steel soon enters the fray, and it becomes all too clear to everyone how strong Doomsday really is as the creature manages to withstand Superman's hits and deal out its own in kind, actually causing the caped wonder to bleed.
Death[]

The fight between Superman and Doomsday goes on for several minutes with much of Metropolis being heavily damaged. While Doomsday's suit has been destroyed, Superman is considerably worse off, having sustained multiple wounds. After the two combatants fall back to Earth after Superman took their fight up into the stratosphere, Doomsday still hasn't tired at all and continues to brutalize Superman, pinning him down and throttling him with his own cape.
Lois Lane stands on the edge of the crater Superman and Doomsday have left in the street. Unable to stand by and watch Doomsday kill Metropolis' hero, she picks up a stone and throws it at the monster, drawing its attention to her. As Doomsday lumbers toward Lois, Superman looks at her and suddenly launches himself at high speed towards Doomsday, pouring all his remaining strength into one last attack. Superman lunges at Doomsday and strikes him across the cheek, hitting so hard that the creature's neck and head twist backwards, finally killing the monster. Beaten, exhausted and broken, Superman dies in Lois' arms, happy that he has saved his city and the life of the woman he loves.