Endermen are tall and exceptionally skinny human like mobs, however with jet-black skin and the strange ability to teleport and getting hurt by water. Drake is known to be half Enderman, however only one whole Enderman has actually been seen so far in any Haunting movie or Haunted episode. This was seen inside Herobrine's lair underneath Iron Mere's capital city in the third Haunting movie, and it quickly disappeared. It is unknown what happened to it, or whether more endermen will be seen again.
Endermen are known to have a vision which inverts all colors. Why Drake's Enderman eye does not do this is a mystery, however it could be because he is not completely Enderman, being half human as well.