http://i43.tinypic.com/2cg1sgh.jpg
It's all up for grabs.
I personally think it's some kind of Witch-related enemy. Their twisted faces, long fingers/nails and use of magic point to such an assumption. You can also make out a withered pair of briasts on the creature in the foreground, possibly signifying that they are human. They are also wearing furs on their torso and feathers on their arms, which leads me to believe they might be some kind of dark druidic cult or sect of Witches that lurk in the caverns out in the back country.
Whatever they are, I was pleased to see them. I'm glad I stopped and said, "Holy sh*t, those actually look creepy!" They're a far cry from Oblivion's Sesame Street looking trolls, cartoon-ish ghosts or the land dreughs (crab people on land? wtf?). I'm looking forward to enemies that look like they can tear you in two, or chase you out of a cave or ruin simply by snarling and lurking in the shadows.
Does anyone care to put their two cents into the bucket?