I recently played as the overlord, and the heroes complained how unfair it was. I chose ettins as open group, and blocked them until I had drawn practically my whole deck. I chose barghests in the second encounter, and since the heroes couldn't kill belthir in their first turn, I frenzied my barghests and killed all the guards in my first turn. Is this fair? How could the heroes win?

Death on the wing is the one where you need to "corner" one hero or put 10 boulders on the canyon to win?
strange.. what party have you in front of you ?
in which position did you do this quest?

In theory if they are 4 heroes they could have removed the minion ettin without too much effort and from there try to race...

And in the second encounter unless the guards have really no luck at all (always 0 shields on the grey dice) and you have always the best roll on the dices (2 hearts+ a surge on the blue and 3 on the red) even with 2 frenzy you could only do 6 attacks !

This implies 2 one shots at least !!
In these condotions .. yes luck is really unfair ! ;-)

Yeah Felin raises an interesting question- you didn't play two frenzy cards (or two dash cards) on the SAME barghest in the SAME turn, did you? Because that is indeed not allowed.

This was the quest that broke up my playgroup. Unfortunately, It took hours to complete Encounter 1. ( Somehow the concept of moving towards the exit didn't jive with one or two players.)

In anycase, I like to use Dragon Hybrids as the Open Group on this quest. They're pretty fast and can do some damage. Also, thematically speaking, I can see Belthir having a few of them around as minions. ( Him being one himself.)

That being said, of the times I've played this Quest, the heroes have never lost. If your heroes are quick, they can intercept Belthir and the Open group before they can do much damage. You just have to realize that you can't sit on the bridge trading Blows with the Elementals on the Bridge.

No. I didn't frenzy the same barghest, the heroes couldn't kill belthir on the first turn but did immobilize him. I have 4 barghests, one frenzy on two different ones, but also dark mights, critical blow, and dark fortunes. Even if that didn't do the job, I could dash elementals to finish off the guards. First turn win.

Heroes: Runemaster Widow Tarha, disciple Avric, Wildlander Jain, Knight Syndrael. I have FOUR barghests. I can easily frenzy two different ones. Really, can someone please explain how the heroes can ever win this quest? Assuming they Can't kill Belthir (who is behind the Elementals) on the first turn, that is.

For starters, killing Belthir on the first turn is very doable. Secondly, depending on how encounter 1 played out, it is not certain that you'll have both or even 1 frenzy-or either of your dash cards. The guards would stand a much better shot in that case. Also, keep in mind that this could be the first, second, or third act 1 quest- so the heroes could have quite a range of skills and gear.

Indeed with all your cards you had more chances to win on first turn.
But even like that this doesn't mean it's an encounter OL have 100% chances to win on a first turn !
even with all those cards, because you could have a twice X, the guards could do a many 3 shields, etc!

And as you could see here
https://community.fantasyflightgames.com/topic/107863-death-on-wings-2nd-encounter-balancing-idea/?hl=%2Bdeath+%2Bwing

EDIT:

or here

https://community.fantasyflightgames.com/topic/135784-how-to-conter-wildlander/?hl=%2Bdeath+%2Bwing#entry1465898

many OL are complaining they couldn't even play !
Of course in this topic it's mainly OL vs 2 or 3 heroes.. but I remind to also have read a message where it was agains 4 heroes..
but don't remind where it was and just now don't have the time to search.. but, by memory, the first hero moved one of the elementals and the three other unleashed all they had on Belthir which have not been able to survive!

So it depends also on the group you have in front of you

Last time I played this Quest (on hero side), the other heroes openned a way (we didn't even attacked Belthir once, if I'm correct) and Quellen as Runemaster when till next room and started to decimate the open group with explosions (not barghests, but with the Runemasters powers not sure it makes a difference ! ;-) ) ..
We ended to loose the Quest on turn 3 or 4, but the strategy stays valid to avoid OL first turn win!

Well with these heroes it looks like the plan is to kill 1 elemental and then try to use heoic feats of Jain/Syndrael to get to barghests and kill them all (or at least 2-3 depending on luck/trap cards) I think that it's much better to kill everyone but Belthir, immoilize him and gather loot than just kill Belthir on first turn.

Remember- the OL needs to kill all 4 to win. Usually that means the OL needs to divide his forces. The guards also can contribute to damage totals. If you have a hero who can move quickly, that one supporting hero can be enough to save a guatd.

I delay the heroes at encounter one, draw practically my whole hand, survive heroes first turn, and frenzy, dark fortune, dark might, critical blow, and dash my way to victory.

Isn't there a hand limit on the OL to prevent those kind of shenanigans?

Isn't there a hand limit on the OL to prevent those kind of shenanigans?

There is a minimum deck size (15 cards) so you can't just distill your entire deck down to frenzy, dash, dark might, and critical blow- but there is no maximum hand size.