Bruce Wayne

On his homeworld of Earth -1, Bruce Wayne suffered a great loss and became the vigilante Batman. He went on adventures with Superman and the Justice League. He sincerely believed in Superman and his ideals of hope, something he would later resent, though he kept the Doomsday Virus as a backup just in case he needed to deal with him for some reason, hoping he would never have to use it.

When Superman went on a killing spree, the League tried to stop him. Despite making efforts for many weeks, they failed and Superman murdered his own wife, which resulted in Batman disregarding any attempt to bring Clark back to his senses. When Bruce faced him with a Kryptonite spear, he lost his right arm in the process. Superman went into a lengthy diatribe about how the League used to claim that Batman would defeat him in a fight and gloated how everyone else was weaker than him. As Superman blasted the spear away from him, Bruce ingested a modified version of the Doomsday Virus. The virus not only regenerated his arm, but gave him the power and the sociopathic detachment to kill his best friend. The mutated Bruce proceeded to first weaken Clark with Kryptonite breath, before he was killed by the spikes generated in the ground by the virus.

After his victory, the Doomsday virus quickly began to spread and infect everything around him, only for the rechristened Devastator to realize it was too late to save his world, watching helplessly as it slowly degenerated and died all around him. Minutes before the imminent destruction of his Earth, he was recruited by the The Batman Who Laughs, who told him of another world, a world where Superman had not yet killed, and where his friends could still be saved and taught how evil Superman was.