I've got a quick question regarding Stamina and Fatigue and can't seem to find the answer anywhere. When a hero has their full amount of Fatigue, do they need to Rest on their next turn or can they keep moving/attacking normally as long as they don't use things that cost Fatigue?

My interpretation as a new player is that it is optional to rest when you want to.

Yes, resting is optional. If the hero chooses to continue acting without a Rest, he is simply unable to spend fatigue on anything. And any effect which forces him to lose fatigue will instead cause him to suffer wounds. But he's not required to rest.

If the hero chooses to continue acting without a Rest, he is simply unable to spend fatigue on anything. And any effect which forces him to lose fatigue will instead cause him to suffer wounds.

Note that the former case only applies to hero skill costs (the number in the lower right) and spending fatigue to gain movement points. Suffering from things like a Master Cave Spider's Web and fatigue expenditure from secondary skill effects or weapon use fall into the case of the latter.