A program for calculating the strength of the guard on random maps in Heroes of Might and Magic III, called H3CalcGuards.

Based on the artwork, I understand that the situation is complex. For now, let's put this issue aside. Regarding the flies, I right-clicked on all the cells around them and didn't find anything. In the game, after the attack, I also didn't find anything. I've attached the save file for that reason.