Lots of interesting thoughts and finds here, but I just wanted to highlight this image is literally a 1 to 1 depiction of the most famous anime Attack on Titan.
The premise is humanity is trapped behind 3 ring walls (about 100m high) and constantly assaulted by mindless, cannibalistic titans - 4m to 15m. They all still have skin and red hair is never shown however, but all of them have silly/clownish expressions.
There's 10 special titans with different abilities, one of them the Colossal is the stripped skin exactly like the image. The defenders use cannons very similar to the image. Their only weak point is their neck's nape, all of them being able to regenerate wounds similar to lizards.
Assuming no one cares about spoilers, it's later revealed their city isn't the last bastion of humanity. They're trapped on an island and the other nations see them as a threat since they started the titans (weird parasite thing latches onto a girl giving her the ability, the idea parasites are a form of demon is quite accurate I think). The world map expands to a titan scale and is actually ours but flipped, so they're stuck on Madagascar - I don't know if that might have any significance. But it reminds me of the "other lands" idea, and how little we actually know - the known world is already fairly large, good luck exploring every patch.
The largest and militaristic nation develops a serum from titan spinal fluid, allowing anyone to become one when injected, albeit the mindless type. So they send their prisoners/rebels off to the island, inject them and kick them off to bully the defenders. For centuries there's actually no "natural" titans, it's all human interference.
For the 10, they're still able to transform back into a human, but they have a 13 year time limit. To pass the abilities on they use the serum to transform someone into a normal titan, and have them eat the human - this allows them to shapeshift back and keep their memories, as well as the new ability. Reminds me how certain groups have focused on the power of our blood - literally life essence and where real magic is. Spinal fluid could also be significant, given it's our electrical wires of sorts.
The ending also has a post-apocalyptic montage, the island city develops into our lovely modern cities, but the other nations invade with modern tech - helis, missiles and such. The city gets decked and amongst the ruins, a boy comes across the same parasite, suggesting a cycle.
I just found it extraordinary how the image matches the show exactly - and from the Aztecs of all people. I don't remember hearing anything about the Japanese creator looking into such legends, but I also don't follow someone's creation process in entertainment.
Someone certainly knows something though . . .