There's a lot of great torsos that have been made for non castle sets that look really good in castle displays. Jedi torsos make great peasants; and the HP sets have wizards, lovely ladies, and the quidditch players are great starts for rangers or fighters.
so, what's your favorite minifig torso that didn't come from a castle set that you have transplanted into your castle world? What do you use it for? -a hero? -a leader? -do you army buld your own unique faction?
My top choice is kind of a cheat, as it was originally designed for a castle set but recolored for a different purpose. The original Blue Goalie from the soccer collection (originally dk gray in the Fright Nights) has been refitted with a black cape, dragon masters helmet, and the star wars yellow Ep1 Anakin face (no smile, freckles). He is now the Prince of the Black Falcons faction, heir to his father's throne, and often leads the BFs into battle using an oversized chrome sword.
Not a favorite, per se, but I also use a bunch of the early Alpha Team Ogel's Minions/Skeleton Drones working as a local(corrupt) police force (one even has a badge to act as 'sheriff') in some village layouts or as support/archers for KK2 Vladek's scorpion knights. They're usually outfitted with Black flared w/noseguard helmets and various (often wolfpack or FrightKnights) heads and use solid lightsaber blades as batons.