Okay I think I'm good with what you have outlined there, if you stick to those examples. The kind of stuff that I'd be worried about is conjuring objects from nowhere (too convienient, you know?) If he has any of that going on, or Teleportation, we might have to prevent him from doing that or learning that.

I think you should put in a permissions post for dragons or dragon-like beings - because you say he can make them obey him. so something like "This is what Merlin can do. Is it okay if he does this to your character?" kind of thing. Could come in handy for plots involving dragons.

Sound cool?