So, my players (the Liberators) just finished up 'The Demonskaar Legacy' and to my incredulous surprise, they actually defeated the demon.
Really, it was pretty much the combination of the Cleric of Kord (wielding 'Alakast') and the Druid (who maxed out his roll for Summon Monster V, and got five dire wolves, which he then 'animal growth'ed). So while Nabthatoron tried to off Alek (which he managed to do), the PCs pounded him into paste.
I will admit that I had him make a decision based on faulty knowledge. When the group agreed to go hunting Alek for Jenya, they asked for official "badges" or somesuch to make it easier on their investigation. She gave them little medallions with the symbol of St. Cuthbert on it, so when the demon saw all these St. Cuthbert-wearing people in the company of Alek, his first notion was to let loose a Chaos Hammer.
But, since the group has absolutely no lawful members, the only person he hurt very much at all was Alek.
I was planning on him teleporting out in the very next round after slaying the Paladin, but the Druid's animal growthed wolves got off a nice round of savaging (when you roll five attack rolls twice due to haste, the chances of a natural twenty or two are quite high) and the Kord cleric decided now was a good time for his feat of strength - and then critical hit - and...
Well, demon goo.
It was a great scene, though. They were very scared, and now feel very chuffed. Definitely fodder for their reputation - and more annoyance for the Stormblades, who keep coming off as their poor cousins.
I think the bit with the chaos hammer was actually a nice touch and a legitimate justification for a minor cheat in what is a very, very tough encounter. Well done.