If you did not watch the Arrow/Flash crossover episode on Arrow tonight you may have missed a very huge reveal. Batman vs Superman's main villain... well it's Lex Luthor, however in pure evil Dr. Frankenstein fashion he creates an "Abomination" out of Zod's body. A monster with a name.... and that name is Doomsday.
My comic knowledge is kinda sketchy so we are going to break it down, and if I missed something or got something wrong please just comment below and try not to castrate me for trying to give you guys the FUCKING NEWS! (I'm sorry that got real really quickly)
Doomsday was first introduced in the mid-nineties and is known most for being the creature that killed Superman. He is basically indestructible and required Superman to body slam him from Mars to Earth to kill him which in turn killed Clark Kent (who is Superman), which makes him a top five villain in the entire DC Universe.
It is obvious however that Zack Snyder and Christopher Nolan are not content with the normal everyday Doomsday as they have added some Hollywood in this concoction and made him a Kryptoniun hybrid monster with all the same abilities as Superman, the military expertise of Zod, and who knows how much extra shit Luther added just for fun.
Doomsday is basically an alien however he was created on Krypton PRE Krypton by an ancient life form. Designed to be the ultimate combat child he was an experiment for decades which concluded in failure after failure until he adapted to the hazards of Pre Krypton. He was unstable and completely indestructible. He was able to escape Krypton and attack the galaxy until being captured by Radiant. He crash landed on Earth raging a war with Superman.
Both the aliens are able to regenerate. However, Doomsday is an adapting monster who learns from past mistakes, making him the ultimate and ultimately the more unbreakable, unbeatable, and unkillable force in the DC Universe.
Let me know if your excited about Batman vs Superman, and thanks for reading. See you soon!