For those not in the know, Malekith is a super-villain in the Marvel Universe, the ruler of the Dark Elves of Svartalfheim.
Here's a description of Malekith's strengths and abilities (via Wikipedia):
Malekith has all the normal attributes of a member of the race of dark elves, although his abilities are as a result of above-average development. He possesses superhuman intellect, strength, speed, stamina, durability, agility, and reflexes.
As a dark elf, Malekith also has the ability to manipulate the forces of magic for a variety of effects, including teleportation, energy projection, physical malleability, flight (by transforming into mist), illusion casting, and the ability to change the shape and appearance of other beings or objects.
Malekith has a vulnerability to iron, which disrupts or cancels his magical spells.
The film, directed by Game of Thrones' Alan Taylor, is scheduled to hit theaters November 8, 2013.