Heart of Chaos

Everything seems good, but... I had one hero, a weakling, who died early on, and he was the only one... and I'm being attacked from two sides with endless waves of enemies. Chaos doesn't care. The enemies aren't a match for him, but to get rid of the demon, I need to take all his cities, and the Dark Elf isn't exactly happy with my dominance on the map. And as a result, I'm stuck: cities in my rear are constantly being captured, and if I go to attack, the demon repels everything because, although the hero is very powerful, he's alone.