Board Thread:General Discussion/@comment-4962906-20151007080647/@comment-25701646-20151013185804

Nimue's not necessarily evil. To avoid spoilers, I won't post the whole story but, let's just say that, in some versions,she had extenuating circumstances for trapping him in a tree.

I say it's a good chance it's Arthur. Supposing they leave out the creepy aspects of Merlin, Merlin could have realized that Arthur wasn't all he seemed to be. As the one who aided Arthur in taking the throne, Merlin would have had the power to dethrone him. If Arthur found a way to turn Merlin into a tree, Arthur would be safe. I don't trust the writers just because they say no Morgan, so I wouldn't rule that out. However, in legends, Guinevere's not always the best person around and she did try to guide Arthur away from helping the Storybrookers.

Also, if Merlin knew the key to defeating the darkness and Arthur, Mordred, Morgan, or really any big bad in Arthurian legends knew that, Merlin would have a big target on his back. It's always possible that Merlin made it look like he's a tree, when really he's in hiding. I mean that creepy usher at the movie theater did seem to know a lot about Emma and Excalibur. Merlin in hiding?