Sadly we didn't manage to balance the castle in time for the end of the jam, so we ended up disabling it to keep a nice game loop!
The build gives a permanent +1 stone and the worker a temporary+2. The idea was for them to cost gold which the enemies were supposed to drop. We will probably go back and add these two things after end of rating period.
I'm glad you enjoyed the idea, I hope you managed to have some fun with the game! Thanks for trying it out!