You know how, in Unfinished Tales, there's a mention of secret cults started by Alatar and Pallando? What if these cults were actually the predecessors of Harry Potter-style magic, and what if they were Merlin's mentors? Or, strike that, what if they were actually Merlin? How did whatever powers they have transform into wizardry? Did they have kids? Students? Or is magic inherent? And what about the morality of giving powers to humans?

EDIT--I've been wanting to write this forever, but I don't have the patience or the Harry Potter knowledge to do so...