It appears as though Christopher Eccleston has been cast as a villain (something I feel like people end up saying alot), Malekith the Accursed in Marvel’s Thor: The Dark World. Eccleston is probably best known as playing the “dark” Doctor in the relaunch of Doctor Who. While his interpretation is my least favorite of the three, he brought a necessary dark side to the character. Between that and his penchant for playing villains in everything, I think this is a good piece of casting.
I’m assuming that because Malekith is the ruler of the Dark Elves, the “Dark World” that the subtitle refers to is the world of the Dark Elves, Svartalheim.
I don’t care either way, I just want to see a Thor film take place primarily in realms other than Earth.