At the start, you have 8 fairies and 10 knights, and the packs are unrealistically large (hundreds of level 1 archers, 30 forest archers, bears, and other level 3 units). The hero has only 20 mana and no mana wells, the hero's special ability is weak, and there are reinforcements, but they cost money that's hard to come by (unless you run around the entire map and loot free gold, but that takes a week or two, and then you have a 6-week timer on the map). The only decent thing that helped (I started playing as a Warrior) was 30 forest archers for 8000 gold, and I barely managed to scrape together enough for them. As a result, I didn't manage to complete it in 6 weeks (I had about 200 out of 300), and I can't even imagine how to complete it as a hero. Overall, you've overdone the difficulty; at least give a larger army so that it's actually possible to clear the starting location and not have to go back and forth, because again, there's a 6-week timer for everything.