Of Kings and Dragons
A giant edifice made up entirely of rosebushes, blackberry brambles, and any plant that carries a thorn, Thornwall Castle is the abode of Mad Jan, King of the Pixies. Jan claims the allegiance of all pixies in northwestern Avistan.
The gardens of Thornwall Castle are reputed to contain every plant that exists on Golarion, and many from other worlds as well. Mad Jan often allows access to those gardens for a price, but that price is always high—usually accomplishing some mission that his pixie minions are too unreliable to attempt.