UTER
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So, you won't be building any additional castles? The Mage Guild requires stone and wood, the Armory requires 14 stones, and if you place Crusaders, the stone cost becomes quite significant. And if you place more champions after that, you'll have to find a lot of wood.
Building other castles is a given, but usually, near other castles, there's a mine and a lumber mill, but stone is not always available!