Walkthrough tips, Discussion of Campaigns [Heroes 5]

It probably wasn't the orange one. The mission conditions state that you can't approach enemy patrols. And even if you win, the mission will fail.
There's also another player. Maybe you defeated him?

I conducted an experiment: I killed the orange hero as soon as he descended into the Dungeon.

Conclusion: underground, the orange heroes lose their patrol immunity. I suspect they lose it even earlier - as soon as they cross the river. No wonder he stood there for a long time after crossing the river before moving on.

In the 5th mission of the 1st Campaign, I leveled up Godrick to level 20. But in the 2nd mission of the 3rd Campaign, his level was reduced to 10. At the same time, all the skills and abilities that he earned through hard work remained with him.

Conclusion: the level of a hero who comes from other Campaigns is either reduced to the maximum level allowed in the previous mission (most likely), or to the level of the main hero of the Campaign.

After completing this mission, Godrick leveled up to level 20 again. That is, in fact, in terms of his skills and abilities, he became a level 30 hero. If his level is reduced again in the next Campaigns, he will become a super-monster of some unknown level.