WARNING: This article contains SPOILERS up to Dark Nights: Metal #6
When Dark Nights: Metal was first announced, it was said that it would change the DC Comics' Multiverse forever. While this sort of rhetoric is par for the course whenever a comic company has a massive crossover event, the final chapter of Scott Snyder's and Greg Capullo's magnum opus has proven that there was no hyperbole involved.
Dark Nights: Metal was based around the revolutionary discovery of a Dark Multiverse - a hidden level of reality based around the nightmares born of every time the heroes might have failed to save the day. The Justice League of Earth Prime was pitted against The Dark Knights (a legion of Batmen who had each taken on the powers of another Justice League member in a failed bid to save their own dark worlds) and Barbatos, a cosmic being of entropy whose purpose was to destroy the universes that had fallen to darkness, so that they might be reforged into something better.
The action of Dark Nights: Metal centered around Barbatos' efforts to destroy the regular Multiverse, leaving only the darkness and decay that were his domain. But he didn't account for the true strength of DC's heroes.
It spoils little to say that our heroes win in the end and that the conclusion of Dark Nights: Metal #6 is largely devoted to setting up the next stage of DC Comics' Rebirth. What is surprising, however, is just what the issue establishes and foreshadows beyond setting up the next big crossover event, No Justice.
The biggest revelation is that a New Age of Heroes is dawning, thanks to the energy released by the collapse of the barriers between The Multiverse and The Dark Multiverse. While this is nominally a reference to some of DC Comics' new line of solo books devoted to original characters like Sideways and Damage, it is also a nod to Scott Snyder's next big project - rebuilding The Justice League line of books.
The book makes the most overt references to this point, with Batman speaking to all the assembled heroes at his victory party about the need to expand The Justice League. He names Hawkgirl (Kendra Saunders) and The Martian Manhunter as two of his new recruits before being cut off. It's also worth noting that the final image of the comic is of Bruce Wayne's desk in Wayne Manor and a blueprint for a building labeled "Hall of Justice".
Another overt reference was made to the upcoming revamp of Neil Gaiman's Sandman Universe. A dream journal written by Carter Hall (the missing, and recently rescued, Hawkman), speaks of how the recent events have altered even The Dreaming. We then see Lucien, the librarian of Dream of the Endless' library, searching for his master and then discovering, to his horror, that a certain book is missing.
Hall's journal goes on to describe several other upcoming events which he has foreseen, which will tie in to the on-going stories of the solo-books of various Justice League members. These include another reference to No Justice and the upcoming Flash War event, as well as the rise of Atlantis from the bottom of the ocean (Aquaman), the creation of a dark pantheon of gods (Wonder Woman) and the return of The Darkstars - a peace-keeping force built to rival The Green Lanterns, formed by the fascist alien race known as The Controllers.
The most disturbing revelation in all of this is a message from The New Gods, who inform the heroes of Earth that The Source Wall - the boundary between the edge of the Multiverse and what lies beyond - has been destroyed. More, it appears that there is something far bigger than they ever imagined beyond their multiverse and it seems that something has been hiding them from the rest of reality. This could be a reference to the events of Doomsday Clock and the belief that Doctor Manhattan is responsible for having created the current DC Comics' Multiverse.
Curiously, there is no mention of what the future holds for Superman in all of this. Then again, it seems likely that DC Comics may be staying silent on The Man of Steel until Brian Michael Bendis officially takes over the Superman line with Action Comics #1000. Regardless, the future is looking bright for DC Comics and it seems that though their heroes still have challenges to face, they have finally made it through the long, dark night of the soul.