I'm torn between Thor defeating both, he and Loki fighting them two on two, or Kurse killing Malekith. I'd like to see Thor defeat them both because it's his film and to make up for not getting to do much in TA's final battle.
Honestly though, I'd like to see Thor defeat Kurse and finish of Malekith's who's getting the upper hand on Loki. Then for Kurse to awaken from being K'Oed and remember that his anger should be directed towards Malekith.
CAPTAIN AMERICA, THOR, IRON MAN, THE INCREDIBLE HULK, BLACK WIDOW, AND HAWKEYE
Spider-Man - It's the end of the world, I'M FREAKING OUT...why aren't you freaking out?
Captain America - Because I can hear it.
Spider-Man - Hear what?
Captain America - ....thunder *cue Thor's grand entrance*