[TheCrimsomBlade]

First let me say Welcome to the Ironworks Forum Korvanik.
This is how I killed the Cultists and the Demon Aec'Letec and none of my team get hurt.
1st,I cast protection from Evil on my mage and my main tank then They drink potion of invisable and runs down to area where the Cultists have raised Aec'Letec. the Tank sneeks across room to far wall and waits,
2nd, Mage cast Cloudkill and the Demon appears. My mage runs back up stairs.
3rd, double click on my tank NPC so you can see him,
4th, drink more invisable potions as needed until cloudkill has disipated and all cultists close to main door are killed then lure remaining cultists and Demom to far side of room when they get close but not to close drink another invisable potion and hide again.
5th, At this time bring mage down again and cast another cloudkill and have mage run back up stairs,this kills remaining cultists and the demon and no body dies but the bad guys.
This worked for me twice now in different big fights. so try it you'll like it!