Doomsday Batman!

"Joker!!!"

A suppressed roar, furious beyond all limits, rang out. Within Batman's wildly expanding body, muscles swelled and burst one after another, spraying streams of blood.

Batman roared madly. At last, he stopped holding back and took out the ultimate weapon he had prepared many years ago.

It was a vial of serum—a vial of Doomsday Serum.

Many years ago, when Donnie was still on Earth, he had suddenly acted and killed Lex Luthor. To investigate the truth, Batman had risked infiltrating Donnie's Estate, and had obtained Lex's brain, along with some unfinished research materials on Doomsday Serum.

Of course, this had also been the result of Donnie deliberately allowing it. Everything had been under his surveillance. Donnie had intentionally handed Lex's brain and a vial of Doomsday Serum to Batman.

Originally, Donnie had intended to use Batman and Lex's intelligence to develop a new Doomsday Serum. But after Donnie fought Ancient Doomsday and successfully obtained the Destruction Spore, he abandoned Batman's side of the project.

Over the years, Batman had never given up on making use of Lex's brain. Lex's level-twelve intelligence was fully displayed through the new brain machine, vastly advancing the grade of the Doomsday Serum and allowing Batman to obtain a more advanced serum.

Although this serum still had a gulf-like gap compared to immortal, endlessly evolving monsters like Doomsday King or Ancient Doomsday, Batman had already fully developed the traits of an ordinary version of Doomsday.

With Doomsday as an example, Batman had kept this serum carefully on his person all these years, treating it as a trump card to be used only when facing an irreversible disaster.

It was also a trump card with no way back. Batman understood the terror of this serum better than anyone. Once it was used, there would be