SPOILER WARNING: The following article contains major spoilers for "Superman" #16, by Peter J. Tomasi, Patrick Gleason, Tony Daniel, Clay Mann and more.

When the Grant Morrison-crafted DC Comics' "The Multiversity" miniseries concluded, for a time it looked like a concept that no other writers were willing to touch. Well, that's all changed as "Superman" #16 wraps up the New 52's first follow-up to Morrison's miniseries, with the universe-spanning Justice League Incarnate and Supermen of multiple worlds joining forces to stop new über-villain Prophecy. And in doing so, we get another glimpse at how the modern-day DC Universe functions, as well as its future.

ECHOES OF THE PAST...

Red Racer's fate results in an homage to George Perez's iconic Crisis on Infinite Earths cover

Part of "Superman" #16 is very much a nod to the past, merging two of the most dramatic deaths of DC Comics in the mid-80s; namely, the deaths of the Flash and Supergirl within "Crisis on Infinite Earths." Both died fighting to save the Multiverse from the horrors of the Anti-Monitor and his anti-matter cannon that would have wiped out the last of DC's many (some would say, infinite) universes. Supergirl's death provided the iconic cover to "Crisis on Infinite Earths" #7, with Superman in tears holding the draped body of his dead cousin with many of DC's greatest heroes in the background, a cover by George Perez that would go on to be homaged for the next three decades and counting. Then there was the death of the Flash, who uses his powers so much that it literally wastes his body away. First the flesh vanishes from his body so that it's just a skeleton inside the Flash's costume, before there's nothing left at all.

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Why is this important? Well, because "Superman" #16 invokes both of those critical moments, with Red Racer using his own speed abilities to build a new Ultima Thule, a craft that can travel between all of the different universes of the modern Multiversity. With Nix Uotan's original craft having taken a millennia to create, the Red Racer burns out his own powers and his life to use the plans for the Ultima Thule to create a second ship capable of jumping universes and saving all of the Supermen.

The effort succeeds, but we're left with the Justice League Incarnate's Superman holding the skeletal body of Red Racer in his arms (with the rest of the JLI behind him), draped in the exact same pose Supergirl's form held in "Crisis on Infinite Earths" #7. Just a nod to the past, though? Or is this a hint that the event being set up by "DC Universe: Rebirth" with be a "Crisis"-level cataclysm, and this is only the first hero to fall?

...GLIMPSES OF THE FUTURE

It would have been easy for writers Peter J. Tomasi and Patrick Gleason to have shown the main villain, Prophecy, to have been a familiar face that was stealing the powers of all Supermen in order to save his own world. But while there's no such revelation, there are some nods to what's gone before. His name, Prophecy, certainly brings to mind the Monitor's assistant Harbinger from "Crisis on Infinite Earths," both promising great things to come. And while his origin isn't quite the same, his multi-universe travels to try and save a world -- although in this case it's quite misguided, with his stealing Supermen's powers to save his own universe -- has hints of the tragic figure of Pariah and his jumping from world to world throughout the original "Crisis," with a message of doom and destruction just around the corner.

The mysterious Mr. Oz admires Prophecy's ambitious, yet flawed, plans.

It's also worth noting that the Multiversity itself seems to have a vested interest in all the Supermen surviving. When the new Ultima Thule appears, Prophecy is shocked to see all of the stolen energies return to the Supermen of the many universes. "The Multiverse dares attack me!" Prophecy actually shouts. Could it be that the primal forces behind all of the DC Universes are somehow ensuring they keep as many Supermen alive as possible? If so, is that why Superman seems to be at the heart of the greater storyline throughout all of Rebirth? Perhaps -- and it's likely Prophecy's description of this Superman as an "anomaly" will play a large part in still developing Rebirth mystery.

Along those lines, Prophecy himself ends up in the hands of the mysterious Mr. Oz by the end of the issue. Up until now, the mysterious hooded figure at the center of what we know about Rebirth has collected known quantities; both heroes like Red Robin, and villains like Doomsday. His admiration for Prophecy's impressive attempt is obvious, even as he describes it as being "unsound." As noted earlier in the storyline, the different universes of the Multiversity all overlap, but remain separated by different harmonics, or sounds.

Could Mr. Oz's plans include a breach of all of the remaining worlds? And if so, for what reason? Could the specter of Dr. Manhattan truly be that fearsome? Whatever the reason, if there was any doubt it's dispelled here: Superman -- the character and comic -- is at the heart of all of these mysteries, and that's most definitely where readers need to continue to read in order to find the answers as past and future continue to collide in the DC Rebirth saga.