natasha
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Message from Prorock
From my experience, I've learned that towers inflict increasing damage each time during a castle siege, if the castle withstands the siege... But if you lose the castle, you'll have to recapture it (naturally), and the towers will fire at you with the same strength as they fired at the enemy (when you were defending)... The downside is that when you recapture a castle with powerful towers, this bonus disappears and you have to build it up again... Maybe it's a bug, I don't know, maybe that's how the towers are designed to work....
To control them, you just need a hero, even at level 1, the most important thing is that he has the Artillery skill (a skill that allows you to control a ballista in battle)... and that's it;)
This is only true for WoG. In SoD, the damage inflicted by a castle depends only on the number of buildings in it. The more buildings there are, the more damage is inflicted.