when activating Worn Down, does the threat token increase the skill cost immediately? in other words, if a hero had 1 stamina left and used a 1 stamina cost skill and the OL activated Worn Down, would the cost increase immediately, making the skill unusable? how would the hero suffer 2 stamina while activating the skill if he cant? if the skill was an action would he now lose that action since he was no longer able to spend the stamina for the skill? i was under the impression that Worn Down is played after stamina and skill abilites are triggered due to the skill being "used" and the threat token would increase cost for the skill for every turn after that, instead of tacking on extra cost immediately like doom does with damage.

The card says you activate it after the hero has used a skill. Descent doesn't like interrupts inside of actions. You generally completely resolve an action before moving on to the next.

I think it's pretty clear you increase the cost of the skill after they have already paid for and used it.

Why do you think it doesn't work this way?

Our OL claimed that the cost increased while we were paying the stamina to use it. In other words, since he's causing the effect he gets to decide the order in which they happen, so he could increase the cost before we even used the skill, keeping us from using that skill in certain situations. That didnt seem right to us. How could the skill be considered "used" if we havent even completed the payment of stamina yet?

28 minutes ago, shang tsung said:

Our OL claimed that the cost increased while we were paying the stamina to use it. In other words, since he's causing the effect he gets to decide the order in which they happen, so he could increase the cost before we even used the skill, keeping us from using that skill in certain situations. That didnt seem right to us. How could the skill be considered "used" if we havent even completed the payment of stamina yet?

Your OL can't decide the order because Worn Down says: "Exhaust this card after a hero uses a class card that has a fatigue cost." He has no choice: it says "after", so he can't chose "before".

Choice of order is only possible when two effects could be seen as simultaneous, which generally means they have the same trigger, such as two effects having an "at the start of your turn" trigger or two players wanting to play an effect off the same trigger.