His name is Rourke!
Remember Ben's words to Locke in "The Man From Tallahassee"? Ben said, "What if I told you that, somewhere on this island, there is a very large box and whatever you imagined, whatever you wanted to be in it when you opened that box, there it would be? What would you say about that, John?"
We know that this "box" is really just a metaphor for the the ISLAND itself!
Rourke wants to create an alternate timeline for Island where he can bring guests and make their wildest fantasies come true!