Po-torr Khan (Earth-4605)

"I came to this world to see if it proposed a threat. Or a challenge. I am not impressed."

- Doomsday

Doomsday is the last surviving Kryptonian in existence and he now travels the universe looking for other races to render extinct.

Trivia

 * Doomsday takes Superman's place as the Last Son of Krypton. In Earth-4605 Superman is a Gallery Comics character.
 * In the end, no single hero was able to defeat Doomsday and they were forced to threaten him with the Ultimate Nullifier, a device with the power of Doctor Manhattan.
 * More to be added...