After the 'death' of Batman who laughs Diana with Wally went to search for the remaining people and make a plan to storm Castle Bat and take back everything that Perpetua had destroyed. Perpetua had been destroying universe after universe so that he could reshape the multiverse from scratch.

There were in total 52 universes in the DC positive multiverse unlike the huge number of multiverses of Marvel so Perpetua didn't have to do much to destroy the universes. She was destroying them for fun and having a good time.

Diana and others were horrified by this and they wanted to bring back everything and everyone. But Batman was not so happy with the plan. She wanted to restore everything but Batman felt that she was daydreaming.

Batman wanted to just have one universe for themselves and didn't care what Perpetua's plans were. Batman knew how powerful Perpetua was and they could never win against her. But the plan all hinged at the point that they needed to take over Castle Bat first.

And thus they made the plan. But as usual they confronted various versions of Batman along the way. In one case, Martha Wayne was Batman. That blew the minds of the people. This was fucked up and that she played minds tricks with Bruce.

But Bruce was too ruthless and just shot her down. But later, when they ran the audience could see tear drops falling from under the mask.

They finally went inside the Castle Bat and they were more horrified by what they saw. The current Earth didn't have a sun so Batman who Laughs and Perpetua had made special measures for that. They had forced Superman to run on a treadmill and the power generated was what gave energy to the prime Earth.

He was made to run in a room which had all forms of Kryptonite attached on the walls so that he wouldn't be able to escape ever. And if that was not enough, Batman who Laughs had put up a guard to look after Superman.

Guard in the form of a version of Batman.

The Darksied version of Batman. Yes, you heard it right. A Batman who had the powers and the body structure of Darksied and even his Omega Sanction!!

"The fuck!!"

"This is bullshit."

"Why is the multiverse hell bent on showing Batman in a darklight?"

Even Bruce himself had a ugly face. Having his own mother on the other side was painful enough, did the multiverse have to show him one more ugly part of his various lives?

Later a terrible fight ensued. Superman was visibly different here as his body was slowly starting to be like Darksied. Superman himself said that he didn't have much time to live in this world and they needed to do whatever to bring everything back to normalcy.

In the fight, Superman noticed that Batman was not hurt at all by the Omega beam of the other Batman. It was there he came to know that Batman had died a long time ago, during the fight against Perpetua for the first time.

The reason he was alive was because of the Black lantern. It was then the audience remembered that the Lantern Ring only takes a dead person as the wielder. Many of the people had forgotten that and those who remembered were skeptical about it. And now their theories proved correct.

Diana went on a mission to save the multiverse. While Batman and Superman went to gather the remaining heroes on all the multiverse. It was possible because Perpetua now was fighting Darkest Night

You are asking who is Darkest Night?

Well he is Batman who Laughs!! Not exactly him but at least the brain behind the new form of Batman was!! When Diana killed Batman who Laughs, his brain still remained. Thus his legion brought the brain back and put it inside the skull of a dead version of Dr. Manhattan.

Dr. Manhattan was a wielder of all the positive forces of the DC multiverse and thus with the help of the body of Dr. Manhattan became one of the powerful persons of the DC multiverse and with this new body he went on to fight against Perpetua.

As Diana was doing everything possible to bring the original multiverse back, Perpetua was losing powers. Batman and Superman were forcing people to remember their past, their hopes and dreams and this made her weak. While Darkest Night was just becoming more strong in the fight.

And finally after a long fight, chugging planets at each other, destroying galaxies in their wake, the Darkest Night was finally able to seal away Perpetua and send her back to the cracked Source Wall again.

Ending the terrifying reign of Perpetua but it was not over as a more terrifying being was now sitting on the same throne that Perpetua once sat on. A more cruel being!