Merlin as Arthur's Imaginary Friend

Hey, y'all!

I'm looking for a specific fic where Arthur grew up having Merlin as an imaginary friend, and they used to play with eachother. Anyway, Arthur eventually ends up banishing Merlin (can't remember whether it was because Merlin showed him he had magic, or because Uther told him to), and regrets his decision. The story eventually ends when Merlin comes back -- as a real person, this time -- as per the events of "The Dragon's Call". It was hosted on ff.net, is probably gen, and is a few years old.

Thanks in advance! :D