Do all players exhaust X characters and discard X cards and add up their total cost to match the Balrog's remaining HP? Feels like this quest would be a lot easier multiplayer if so. Or is it just one player? My gf and I tried this scenario for the first time tonight. We hung in there for quite a while, but eventually lost due to inability to keep questing and sacrificing allies. (Lost a hero early on due to Leaping Flame (?) and the Balrog got Fiery Sword which didn't really help.

It would just be one player-- whoever triggers the action. Any player can trigger it, but you can only exhaust characters controlled by the triggering player.

If you whiff on the first chance, another player can then trigger the action and give it a try as well. Of course, if everyone fails it, that is quite a few characters who will be exhausted through the next round...

I see, thanks! Yes indeed. We did get to the third stage, where I lost my second hero due to the immediate attack effect (too few allies in play). Her deck, including Gimli and Gloin, kept going for the balrog and damaged it by 4 (-3 Regenerate) every turn. I guess we could've made it in about 25 turns or so, but our threat went up past 50 when we miscalculated and didn't quest. We'll get him next time!