Skyrim patch 1.5.26 appears to have inadvertently revealed details of the first DLC, due to be detailed further next week.
The patch contained animation files with character strings suggesting the inclusion of Snow Elves, a Snow Elf prince, crossbows and vampires.
The Snow Elves were a race of elf which lived in Skyrim before the Nords. These elves turned into the Falmer after spending hundreds of years underground forced into slavery by the Dwemer.
Whatever its contents, the DLC will initially be released exclusively for Xbox 360.
Via Skyrim fan Kerellan