SPOILER WARNING: The following article contains major spoilers for Dark Nights: Metal #2 by Scott Snyder and Greg Capullo, on sale now.
In the first issue of Dark Nights: Metal, we learned that Kendra Saunders, the former Hawkgirl, is now known as Lady Blackhawk and that she has been investigating the mystery of Nth Metal for quite a while now. In Issue #2, though, we see Kendra visit a secret base (that happens to be the same base that the Legion of Doom used on the Challenge of the Super Friends, which was prominently used during Forever Evil) and meet up with a select group of DC characters who are all, in their own way, immortal. And while the mix involves those who are clearly heroes as well as those with more villainous tendencies, they all appear to be working in concert as a sort of Illuminati, formed to protect the DC Universe.
We figured that it would be helpful to fill everyone in on who these people are, exactly, so we'll explain who everyone is, starting with the non-obscured characters, working from left to right.
Created by Will Eisner for Quality Comics (back when Eisner was running one of the top comic book "packaging" studios, which was a group of comic book creators who would produce finished material and then sell it to comic book companies who would then publish it. Eisner gave up his stake in this company to launch The Spirit comic book series), Uncle Sam originally was a mystic hero who was the soul of a murdered American Revolution soldier who returned to fight for American freedom in the present day.
When DC Comics took the character over, he was assigned to Earth X, with other Quality Comics characters, as the Freedom Fighters, who had to fight on a world where the Nazis had won World War II. Uncle Sam was now the spirit of America itself, who would just possess new hosts over the years and they would be empowered by the strength of the country.
Rarely do comic book characters change quite as much from their original incarnations to their present day ones as the Phantom Stranger, who debuted as a character whose gimmick was to debunk alleged supernatural events. Over time, it became clear that the Stranger himself was supernatural, at which point the stories took on a more fantastical nature. This might be why his powers are so ill-defined, as he did not have any originally.
Over the years, the Stranger's most common use has been as a facilitator for supernatural plots for other superheroes. He even sort of joined the Justice League of America in that role, where he would show up, alert them to a supernatural occurrence, bring them where they needed to be and then sort of disappear. The Stranger famously also doesn't have a clear cut origin story, as a bunch of different writers (including Alan Moore) have instead come up with possible origins for the character.
In the modern DC Universe, Mamaragan is the current Wizard who gave Billy Batson the powers of Shazam. He is the equivalent of the pre-New 52 character of the wizard Shazam. Now that DC has decided to not call Billy Batson's character Captain Marvel at all, but rather Shazam, then suddenly the wizard also being named Shazam was very confusing. So now he is Mamaragan, the last of a group of mystical beings who ruled over the world of magic millennia ago.
Now he transferred powers to Billy Batson, but during the Darkseid War, he ended up having to come up with new gods to use to give Billy powers, and as it turns out, he, himself, was one of the gods used to power Billy today (he's the M part of Shazam, naturally). He's a slightly less distinguished version of the original Wizard.
MORGAINE LE FEY
Few artists in comic book history could design costumes like Jack Kirby could. Other artists might draw even better costumes, but few could rival the sheer manic energy that is present in many of Kirby's designs. Morgaine Le Fey's golden armor is certainly one of those designs - the ornate helmet, all of it is just so over the top that it is utterly wonderful.
In any event, Morgaine Le Fey is based on the character of Morgan Le Fey from the King Arthur stories. Here, she is responsible for the downfall of Camelot, but Merlin is able to hold her off by bonding the demon Etrigan to one of Morgaine's own men. Etrigan and Morgaine then were bound against each other for centuries since then.