Ah. Perhaps I was mistaken, then; while the likeness is not perfect, you do bear many similarities. The Star Swirl that she spoke of was, at one point far in the past, this world's most powerful.

You are in a variant of the world of Equestria, Merlin. A power that is not your own has brought you here, and many, myself included, believe it is the land itself that has changed you into the form you are in, as a protective measure to prevent the influx of humans and other such creatures.

If you desire, I can answer any questions you may have, though I cannot promise that every question has an answer.