Magic: the Gathering in the UK
Sweet. I'd definitely draft it.
Does the "unknown to the rest of their faction" manifest mechanically? Are there some white cards with Black abilities and some White cards that suffer if you use Black abilities or Black spells?
Why 301 cards? Have you decided how the 301 break down into Creatures, Instants, etc. (and colors)?
I love affinity for enemy-colored lands. Nice.
Not sure about "~" as a name for the plane :)