White lantern is the most powerful lantern and John could bring the entity here because there was a shortcut in bringing him. At one point of time all the members of the Justice League were White Lanterns. This happened in the Darkest Night series and with the help of White Lantern all the deceased superheroes were brought back to life who had died over the course of time.

Even Aquaman who had died was brought back to life with the help of White Lantern ring. John could bring the entity easily but it had to be remembered that not many white lantern rings were made and only a few wielded it in their lifetime.

Wayne was right when he said that having a white lantern was probably the best security here but then again, it would be his summon and it might again prove to be a liability. So John would have to be sure before summoning the white lantern entity.

John was in deep thought as he saw that Urahara and Mayuri were talking on a particular topic.

The topic of Bakudo!

Bakudo was a kind of spell that binds people or things and keeps it under a seal. Many of the anime used this For example, it was used to seal away Aizen and the Shinigami used it in different cases to seal away things which they thought would be impossible to kill. even Aizen himself used bakudo on Ichigo when he thought that Ichigo was too powerful for him to handle.

Of course at the end Urahara came to finish the job for everyone. Another scene where bakudo was used was during the 4th great ninja war. When many of the deceased shinobis were getting resurrected left and right, the nations decided to seal them instead of trying to kill them which was proving to be impossible.

At the end they were successful in sealing many shinobis who were too much of a menace. So all in all bakudo has come in handy in many tricky situations. And so, this time too Urahara and Mayuri had decided to make new seals and bins surrounding the crack and monitor if there is enlargement in the crack.

This whole situation would take a lot of time as they would have to try every different seal on the crack. While this was being decided by the Shinigamis, the scientists of their side were going through the technological route. The good old route.

Of course they would have to see if the magical route was possible in this sealing of the crack and for that Doctor Strange from Earth TRN891 had also come with the whole team. He was here for the magical side. Since the other Strange couldn't just leave their Earth being the Sorcerer Supreme, Doctor Strange asked help from Clea (Wife of Dr. Strange, she was in the post credits scene of Multiverse of Madness. She is the current Sorcerer Supreme after the death of Dr. Strange and previously she was the Sorcerer Supreme of Dark Dimension, yes the same dimension of Dormammu)

So they had guns from all the sides possible from the multiverse, now the question was if their bullets were good enough to stop the enemies and seal the problem once and forever.

John stayed at the Harvester for quite a few days to see if there was a problem with the system. He had talked with it and tried to pry out its secret. But all he got was silence. But all he could gather from the system was that it did really come from the Wall and it didn't have any malice to the multiverse.

John didn't know if he could believe the system. For sure it had helped him in his quest to gain power and lead a good life. Now all he had see was if the system was truthful to him or not. Like others, John too had to go for evaluation and had to go through many interviews with Bruce to bring out his weakness, if there was one.

After multiple interviews Wayne figured out his weakness as his friends and family. That was the only weakness that could be gathered as his strength was already off the charts. Of course John had access to his own weakness as he himself was the summoner of Wayne.

Finally after a few days staying at the Harvester, John left for his home. He didn't need the help of Oblivion this time. He already had the coordinates saved by Nabu and if he ever wanted to come here he would be able to easily come back by portals to this location of the crack.

After saying goodbye to his friends and a little tearful Emma, he vanished away and was back at the Ring. Before he left for the Void, he had sent the Avengers of his Earth to their home so that they could be back.

Even the X-men were back at their new home or rather their moon.