Scorp, please upload the save file so we can analyze it and figure everything out. I've added something – I think I know what the problem is. I encountered a similar situation in Heroes 2. I figured out what was happening: if a hero attacks diagonally, the move is counted as if they were moving in a straight line. This means that when attacking neutrals, instead of deducting 141 movement points, it deducts 100. If there was only one battle, Mephala could have dealt 1720 damage, theoretically, and assuming she started with 1700. In short, we need the save file. Ideally, it would be the starting save, but I doubt that exists, given that it's turn 111. But I hope we can still figure it out with this one.