Yagerna is dead as for Berhlihn I cannot say because I never did that ending
I left the B****** rot in his prison lol
@ Raze - I know my speeling is s*** lol but hay at least you can all get what i'm saying

I did that ending too. It does not say what happened to Berhlihn presumably as you say he was left to rot and stayed that way.
Aida - I completed it in one go, didn't die once. I used the 'nuke' aka wrath of the patriarch (mapped to 2 on your game) on the big groups and lightning towers. Healed using healing spell when health got to around 50% and used shield a few times. Used wyvern as a distraction when going through the nests & groups of ballistas to keep some of them off me. Kept moving to dodge ballista attacks as they do the most damage to you. It's just a matter of strategy of attack rather than just pressing spell hotkeys randomly. Keeping ahead of but not too far from the airship is the way to do it. Don't bother ordering them to attack targets the npc ai will do a good job on it's own. Ship health was around 25% when stage complete. I also had had a couple of pints of beer before playing it - maybe that helps!

I completed aida's game to see the alternate ending; my guess Yagerna died for good & Berhlihn was imprisioned. Prehaps Larian have plans for him to be in Project E?