Doom in the Dark Multiverse (Pages 19-24)
Page 19 shows us where the four teams are headed. Bialya is a fictional DC-Earth country created by Keith Giffen and J.M. DeMatteis. First appearing in June 1987's Justice League #2, it featured prominently in various Justice League International storylines and was a very loose pastiche of Libya under Muammar Gadhafi. Bialya's history took a dark turn in the 2007 miniseries 52: World War III, when a vengeful Black Adam murdered the country's entire population while looking for the monster which killed his family. While subsequent timeline changes might have undone all that, there still might not be much inside Bialya.
Besides Thanagar, the Polaris System also includes the worlds of Polara and Rann (the latter recently relocated from the Alpha Centauri system). The intergalactic tyrant Despero wounded Thanagar's longtime Green Lantern Isamot Kol in the Death of Hawkman miniseries, so Kol's ring chose Hawkman's friend Rayn Kral as a temporary replacement. Between them and the Rannian Lantern Vath Sarn, Hal, Terrific and Plastic Man might have some local help.
The Mariana Trench is located in the western Pacific Ocean near the Philippines and contains the deepest point on Earth. In a sense we suppose that makes it "beneath Atlantis," but since Atlantis is traditionally in the Atlantic (hence the name), we're a little confused by Aquaman's comment.
We saw in the Forge special that Batman had put a Monitor tuning fork (which Steel calls an "antenna") beneath the Fortress of Solitude. We're not sure that Steel's memory of it as an Anti-Monitor device is quite accurate, but he wasn't a superhero at the time of COIE. He could also be remembering the device from Infinite Crisis (when Alex Luthor reconstructed one using parts of the Anti-Monitor's corpse); or he could have seen one of the originals on the news when it materialized in the middle of New York City in July 1985's COIE #4.
The Phantom Zone (mentioned on Pages 19-20) first appeared in a Superboy story in April 1961's Adventure Comics #283, written by Robert Bernstein and drawn by George Papp. Discovered by Jor-El and used as a Kryptonian prison, it's a limbo-like dimension where "inmates" spend eternity in a ghost-like state of existence. They can see what's going on in the regular universe, but they can't interact with it. For the most part, the only way in or out is through the Phantom Zone Projector; although there is a physical way out (as seen in January-April 1982's Phantom Zone miniseries by Steve Gerber and Gene Colan).
Page 20's observation that "there's nothing darker than making a hero the lever for evil" is particularly ironic coming out of Superman, since Evil (or at least Dark) Superman has been quite the trope in recent years. Off the top of our heads we're thinking of Injustice's Totalitarian Supes; Red Son's Soviet Supes; the Apokoliptian Stooge Supes of Batman v. Superman's "Knightmare" and the New 52's Earth 2; the Jokerized Supes of Snyder and Capullo's own Batman arc "Endgame"; and the Nazi "Overman" from Grant Morrison and Jim Lee's Multiversity chapter "The Master Race." Metal's Dark Knights are so scary they've almost balanced the scales, but for a long time the Bad Batman was represented mostly by the tortured souls of the Red Rain vampire trilogy and the Thomas Wayne Bats of Flashpoint; and (sort of) by Mark Millar's sociopathic Nemesis.
Superman plans to "open a portal with the Phantom Zone Projector while [super-charging] the antenna with the Speed Force" and using Steel's Nth Metal hammer to "create an energy link to the Dark Multiverse." Given that the Flashes' innate dimension-hopping abilities come from their vibratory-frequency control, Supes isn't too far off. (Note that not everything with super-speed taps into the Speed Force. Superman's speed comes from the hyperefficient solar batteries in his Kryptonian cells.) Anyway, essentially they're using the antenna/fork as a hopped-up version of the Flash's Cosmic Treadmill, which allowed Barry Allen, (Classic) Wally West and Jay Garrick to travel through time and across dimensions. Jay and Wally built a gigundo Cosmic Treadmill to transport a superhero army to three besieged Earths in December 1985's COIE #9; and Jay, Wally and the Supermen of Earths-One and -Two used the regular Treadmill to try and find Earth-Two itself in February 1985's COIE #11. (Spoilers: it wasn't there anymore, although some crackling dark energy was.) This expedition seems closer to the latter.
The "golden" Superman of Page 21 reminds us of the golden Prime Superman who'd exiled himself to the core of the Sun in 1998's DC One Million miniseries. Here, we presume that Supes is golden because he's charged with Speed Force energy. On Page 22 we see him starting to burn it off.
Naturally, Page 22's "B-66" reference is for "Batman '66," so we suppose the Batman Who Laughs wants to hear some Neil Hefti as an ironic accompaniment to Superman's ill-fated arrival. On Page 24 Batman himself explains that the "Batman '66" theme was his sonic warning, because it started on D and went down to C (for "don't come?"); whereas the proper code was the opposite, C-D. That's what Superman gets for dwelling on the merits of the tunes!
Indeed, it's doubly ironic because Superman himself had to "sing" the Multiverse back into existence at the end of 2009's Final Crisis #7. If vibrations are critical to the Multiverse's existence, and music is basically just vibrations, then a music-based Multiversal crossover isn't too far-fetched. Here's hoping the Batman Who Laughs doesn't call up The Doors' "The End" anytime soon....
Finally, we disagree a little with Batman's Page 23 observation that music is "the only way to communicate across the Multiverse." In September 1961's seminal "Flash Of Two Worlds" from Flash #123 (written by John Broome, pencilled by Carmine Infantino and inked by Joe Giella), Barry explains to Jay that on his Earth, "a writer named Gardner Fox wrote about your adventures – which he claimed came to him in dreams! Obviously, when Fox was asleep, his mind was 'tuned in' on your vibratory Earth! That explains how he 'dreamed up' the Flash!"
Granted, it's only one-way communication (if it even exists beyond Barry's supposition), but who knows? After all, the Dark Multiverse itself is made up of all those nasty impulses and unwise choices, and they're not entirely musical.
What did you spot in Dark Nights: Metal #3? Let us know in the comments!