I'm working on a small series of connected games I'm going to run this spring at KublaCon. The antagonists/players will be representatives of the Eastern King, normally considered the villains. They'll be fighting representatives of the Western King. If you've read Tim Powers'
Drawing of the Dark the premise will be familiar. The first game will have the players trying to make of with or kill the Tower ravens, which would signal the beggining of the fall of the West.
Merlin, Nimue and eventually an Arthur type will be some of the NPC's representing the West. I've done a pair of conversions to represent Merlin and his protege, Nimue

