Uninvited guests.

Playing as Humans, Dugald won the map (final, “hero”) in 165 days. First, he found a bow, then he acquired a quiver from some hero, and the “archer’s dream” was complete. He hired Elaine at the tavern, which made things much easier financially. But to finally crush the AI, two practically equal heroes were needed. He bought Iris and, through mentorship with Dugald (level 33), leveled her up. He gave her all the griffins that he hadn’t been buying at the Castle since the beginning of the game. From that moment on, the computer lasted exactly as long as it took Iris to conquer all the enemy Castles.
I didn’t like the fact that the AI generates armies for free, as a derivative of the game time. This turns everything upside down. The most formidable opponent was the Necromancer, and the easiest was the Dark Elf. The AI attacked with everything it had, an incredible beast. Dugald broke through the gates, and the Necromancer captured the Castle. The Dark Elf hero was first attacked by the Demon hero, then by the Dwarf hero, and only then was Dugald able to defeat him (all battles in one day). As a result of this troop distribution, the Necromancer looked very ridiculous, leading a huge army of undead from the Dark Elf Castle (he had no other).
The other side of the same coin: prolonging the game leads to a loss. And the higher the difficulty level, the longer it takes to build up armies, i.e., the higher the chance of losing. (The map is practically “tailored” for the Dark Elves.) The condition of holding your own Castle leads to prolonging the game. It takes 7-8 days to travel there and back, even with logistics, stables, and a “city portal.” At least one AI hero will attack your Castle during that time, and only your own hero can defend against them. If you have already captured an enemy Castle, you need to be very careful when moving around the map, otherwise the “portal to the city” will not return your hero to your own Castle at the right time. Therefore, I suggest either that the captured AI Castle should be destroyed, or that the teleport should only transport you to your own Castle.
In the appendix, the last battle: Ravenna vs. Dugald; the map will be completed in 3 days. Ravenna has an army from an empty Dark Elf Castle.
P.S. I almost forgot about Rupert. He’s a suitcase without a handle; even at level 30, he took up valuable space in the shelter throughout the game.