"Thor: The Dark World" will introduce the Dark Elves of Svartalfheim into the Marvel Cinematic Universe, and here's one of your first peeks at what they're going to look like.
Their masks look like they could just as easily come from a Guillermo del Toro movie, or even an "Eyes Wide Shut" party gone horribly wrong. (Well, more wrong, I suppose.) The "Game of Thrones" influence that director Alan Taylor brings to the table appears to be on display as well; there's something almost Weirwood about these masks to me.
Taking the masks out of the equation, we can get a good look at what the Elves' faces look like: half of it is pale as snow, half of it is dark as ashes, all of it is thoroughly intimidating. Thor's new enemies clearly mean business.