For the last few months we've seen explosions and devastation from The Avengers, but not who was creating those explosions and devastation. Now the Super Bowl ad has shown us the army that our hero fights and they're... unidentifiable. What follows is a lot of speculation, informed by some slightly spoilery insider knowledge about elements of the script from BEFORE shooting. Things may have changed since then.
But be aware there are MINOR SPOILERS AHEAD.
The image above is a screen capture from the trailer, and the creature shown is not obviously any known Marvel Universe race. They definitely have a Norse look about them, and given that Loki is the main villain of the film, that makes some sense. Rich Johnston of Bleeding Cool has a big post claiming they're from Muspellheim, as seen in Walt Simonson's very famous Surtur Saga in Thor. I think a big part of his argument comes from assuming that a lightning strike on the Chrysler Building is the beginning of the invasion, and that the creatures are jumping from the art deco arches of that building in the image above. I don't think that's the case, but I don't discount that the creatures could be Norse.
Here's the thing: in the original script draft they're aliens. But that's all they are - 'The aliens.' They have no name.
They have a Leviathan, whatever that is. Online speculation has that being a sea monster, maybe even Fin Fang Foom. That would be very cool. The Leviathan could certainly be an Asgardian beast of some kind or it could be an alien beast.
While 'the aliens' in the script have no name, they do have one distinguishing feature.
This is probably the biggest spoiler, so beware.
They change shape. It's actually a pretty important element of the script - but again, what I know is from an earlier script. That said, it's such an important element of that earlier script I'm not sure how it would be changed. I guess that since Loki has the Cosmic Cube he could do anything he wanted, including altering the shape of a creature. Actually, Loki could probably do that with a spell if he so wanted. So maybe I've answered my own question.
What keeps me unsure of anything is that I know the original script had a surprise villain (who was revealed elsewhere online; I won't spoil that here, but you can find it if you search) who is very cosmic. The impression I got was that Marvel intended to use The Avengers as a launching pad for their space/cosmic characters, who are in the next wave of projects under development. Guardians of the Galaxy is very much moving forward into the script stage, as is The Inhumans. But what good does bringing in more Norse characters do Marvel when it comes to outer space movies?
It's hugely possible that the info I have is outdated. There was another draft of the script completed right at/during shooting. And the vagueness of 'the aliens' was surely intentional; I suspect that Marvel was hoping to have The Skrulls legally available.
Still, these creatures could be the Chitauri, the Skrull-like baddies from The Ultimates, an alternate universe Avengers. Or they could be the Dire Wraiths, bad guys from the ROM Space Knight comic who made a major impact on Marvel Comics back in the 80s. The creatures above look nothing like the shape-changing Dire Wraiths, but the comic version of Dire Wraiths are super, super stupid.
Or it's more Norse stuff, leaving The Avengers completely a sequel to Thor - a strange turn of events, I think.
What do you think? Speculate wildly below.