Aec'Letec

Aec'Letec is the final 'Boss' following the completion of Durlags Tower Dungeon. It is a very hard Demon to defeat, mainly due to the special abilities it uses which will cause characters to 'Gib' with no save (Die Permanently, cannot be raised), and turn into Hostile Ghouls.

Location
Aec'Letec can be found in the basement of the two-storey warehouse on the western side of Ungolths Beard after the Soultaker Dagger has been aquired.

Strategies
You will probably want at least two clerics or two mages, or one cleric and one mage in order to deal with his Gase attack. Key Spells to have Memorised are Dispel Magic (Level 3 Wiz/Cleric), Animate Dead (Level 3 Cleric) and some form of Remove Fear.

Upon entering the Inner Sanctum an NPC named Tracea Carol will start talking to you. As soon as this dialogue is finished the fight will start. Aec'Letec will spawn in the center of the red circle, and there are a number of NPCs named 'Cult Guard' standing passively around the outside.

Death Gase Attack: Aec'Letec will cast a spell on your characters which first acts like a Hold Person spell, and will also add a debuff named 'Dying'. This can be countered in only two ways. The easiest way is by use of the Dispel Magic 3rd level Cleric and Mage spell. Yeslick is good here for his special innate ability to cast Dispel Magic. This has a downside however as it will also dispell any buffs you might have cast. The other, and less preferable way to prevent the permadeath of a character affected by the gase is to litterally Kill the Character before he turns into a Ghast. It is not advisable to do this if the protagonist is the recipient of said Gase, for obvious reasons.

Vampiric Touch: Aec'Letec will frequently cast this spell on anything that comes into touch range with it. It heals the demon and increases its survivability considerably when anything other than undead minions attack it.

Magic Resistance: As a denizen of the lower planes, Aec'Letec has a very high Magic Resistance making it difficult to harm it with spells.

Immune to Normal Weapons: Aec'Letec cannot be harmed with normal weapons. Enchanted weapons must then be used.

Summoned Skeletons are very good at keeping his attention (and the occasional Gase attack) away from your valuable party members. If he lands a gase on any target it will after a few seconds Gib and turn into an Undead Ghast/Ghoul, preventing any form of Resurrection, so its best to let some poor summoned creature eat it instead of them.

If Aec'Letec is killed while any Cult Guards are still alive, he will re-incarnate at full health from the body of the Cult Guard and the fight will continue until no Cult Guards are left alive.

By summoning undead creatures directly on top of Aec'Letec, then dispelling magic whenever he casts his gase on a party member, the characters in the party should be free to move around the outside of the circle killing the Cult Guards. If you run out of Skeletons to summon, casting otiluke's Resilient Sphere on the target he is attacking can keep him occupied for a while. Once all the Cult Guards are dead, it is a simple matter of finishing off Aec'Letec for good.

Aec'Letec is worth 16,000 xp. Each Cult Guard is worth 500 xp.