- по Heroes 3

Message from Prorock

From my experience, I've learned that during a Castle siege, Towers deal increasing damage with each attack, if the Castle withstands the siege, and this damage increases over time... But if you lose the Castle, you'll have to recapture it (obviously), and the Towers will fire at you with the same strength as they fired at the enemy (when you were defending)... The annoying part is that when you recapture a Castle with special Towers, this bonus disappears, and you have to build it up again... Maybe it's a bug, I don't know, or maybe that's how the Towers are designed to work....
To control them, you only 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;)