Castles are obtained in Story Mode by completing story objectives at the end of each chapter. They can also be rewarded randomly from the King in Normal Mode and Battle Royale for killing Big Monsters.
A player may heal their health at any castle for a fee, or for free at any castle that player owns. If they do not own the castle, the fee to heal tends to be substantially more than healing at a city.
The net worth of each castle is equal to twice the value of the most valuable player-owned town on its continent. If the most expensive town's base worth is increased, or another town is increased beyond the most valuable town (either by investing or by the Mitch Digger random event), the worth of the castle on that continent will be increased.
Castles start producing Local Items immediately.
If the most valuable city on a continent is rendered neutral, either by summoning a Monster or the acts of the Darkling, the castle will revert to being worth twice the value of the highest owned city. If no cities on a continent are owned by a player, a castle will be worth zero gold.
When a player lands on their own castle, they have the option of investing any amount of money they choose. Invested money does not increase the value of the Castle, but it increases the Local Item Value of the Gem it produces. Castles do not have levels like towns.
The only way to steal a castle is to become a Darkling and use "Castle Panic."
Castles have the chance of generating gems of varying types that can be sent to the king, either by visiting the castle or by sending them via a temple.
ID Name Seen 1 Khan's Castle Asiana 2 Rhine Castle Hallstatt 3 Yukon Castle Clovis 4 Cusco Castle Llano 5 Strom Castle Gunnbjorn 6 Keller Castle Aphrike 7 Bathur Castle Flinders