Hi, I have a question about the trigger of special ablity of the scourge.

The ablity say "Each time a hero adjacent to the Scourge suffers 1 or more Fatigue from an effect other than this, choose another hero to suffer 1 Fatigue."

What is considered an "effect"? Does spending fatigue to activate hero abilities or to gain movement points triggers this ability?

The wording is to avoid loopings
So everything is an effect

Yes ! speding fatigue to MP triggers the ability... so better to transform all fatigues at once if you want to turn arround the Scourge ...

An effect can be a result of a monster ability, an overlord card, a quest rule or even the hero volontary spend fatigue for any reason