I'm also having issues with the quest crashing around 10 seconds every time no matter the map configuration. It seems to happen after one of the peasants spawns from the Palace. I did the revelation cheat to see if it was something the AI kingdom was doing, but didn't see an activity before the crash. That being said according to my game files I've beaten this quest before in 37 days so it seems I did manage to run it at some point, though it's been years since I've had Majesty and this mod did get released a while ago and I'm wondering if the quest got updated since then.

I open it and after 10 seconds it closes. Is there a way to fix that?

This quest really needs something other than demonwood to train heroes on. I've repeatedly had to rely on ballista and wizard towers to expand while my level 1 Paladins staunchly refuse to even leave their houses. I do however like the nice buffer that demonwood provides between my rival and I.

Very good quest. It wasnt easy but it wasnt hard.

I had a nice brawl :)