Demon invasion.

Started a new game. This time, the yellow faction appeared very early in the second month, with an even larger army than before. However, when I retreated to the thieves' guild, it didn't attack me but instead ran towards the blue faction. The blue faction defeated it, but was left with almost no army, and I managed to kill it, albeit with significant losses. I took the blue faction's castle, and tried to approach the yellow faction's castle – the orange faction appeared, even stronger than the previous two. So, I'm staying in the blue faction's castle for now, clearing the surrounding area, collecting artifacts. The orange faction doesn't seem to be attacking yet, and if it continues like this, I'll eventually gather enough troops from the two castles to defeat it. But without this random AI behavior, I can't imagine how to complete the game. The enemy armies aren't significantly larger, except for levels 6-7, but they are equipped with artifacts, and the yellow faction has a powerful Chaos skill, while the blue faction actively uses Berserk and enhanced spells, making it difficult to win. I need to find a way to weaken the enemies, at least on lower levels than the hero.