A stuntman working on Thor 2: The Dark World might have given away the film's baddies -- Dark Elves.
I had a load of stunt guys in and the director came in and he said 'Look, we want you all to be elves,' and I was like 'What the hell is an elf anyway?' and he said 'I want you all to walk around like these supernatural animals,' honestly it was the most ridiculous thing ever but you just have to not be self aware and get on with it.
Elves are nothing new to the Marvel Universe, and Norse mythology, too. But remember, this is still just a rumor.