Challenge maps

I got to this point on the map. I reached the guy who has 100+ times more level 7 units than I do, and instead of being horrified and yelling "forget it, this is ridiculous," I started thinking about how to beat him. 262,136 ghost dragons is a lot. And people still get upset and wave their hands when they see 100,000 archmages in Paragon after a bug. :D I wonder, is it even possible to beat the last battle without exploiting bugs? Well, if this were the final battle on some large map, where my hero had the necessary skills, a cart full of supplies, a backpack full of artifacts, almost all the spells, etc., then even with such an imbalance of power, I could probably win in a fair fight. But here, my army is two orders of magnitude weaker, and there are other restrictions. The worst thing is that my water magic is not leveled up. I can't even heal properly. But I'm an expert at pathfinding. :D Okay, forget about water magic, but how annoying is his dispel? I'm just sitting behind a force field, not bothering anyone. Every round, he summons a dragon clone, gradually draining my mana. And then, suddenly, he dispels my force field, and that's it. And he does it completely randomly. He might cast it almost immediately, or when he has 500 mana left, or when he has 50. Once, he had only 4 mana left, and I was already rubbing my hands together, wondering if I even had a chance of winning fairly, and then he started hitting me with Titan's Lightning for 3-4 rounds, and then, with the remaining 4 mana, he simply dispelled my force field and killed both of my stacks in 1.5 seconds. So, if I had expert water magic, a permanence sphere, and an amulet that protects against lightning (if it even works against Titan's Lightning), then I probably would have had enough mana for a fair fight. But that would be lame, and the battle would be too easy.