Su Ming had always had a plan—or rather, a plan he had picked up from The Batman Who Laughs.
Originally, in The Batman Who Laughs's hands, it had been intended to drive every citizen in a certain Gotham insane. Now, its existence happened to give Su Ming a way to spread White Lantern energy.
As long as different Parallel Worlds had a city called Gotham with a complex sewer system, it meant their construction processes had been more or less the same.
And the Forerunners of those great families had once secretly built a city cleansing system: the "Final Laugh."
It could release highly concentrated poison and flammable liquid throughout the city, kill everyone, then purge everything with blazing fire. It simply had never been needed after it was built.
Now, Su Ming only needed to find that equipment underground, replace the poison from centuries ago with another medium, pour in a massive amount of White Lantern energy, and use it to spread that energy across the entire city.
He knew where the Earth-0 equipment was. For Earth-12's, he merely needed to search the neighboring area.
At the same time, eighty percent of the buildings in this Gotham contained Amber Gold. This had originally been part of the Court of Owls' arrangement, but now he could use the liquid pools in the Owl Maze to resonate with it, try to awaken Earth-12's Crisis Energy, then play the good guy through the White Lantern Ring and see if he could draw out the Entity of Life.
With both approaches going at once, they would most likely clear out every Black Lantern Zombie in the city. If any slipped through, he could just fly over and finish them off.
After Su Ming explained his plan to Laurie, she also thought it was