The cult consists of:
- Cult Guards: 8th level fighters. Their hit points are increased from
39 to 65; otherwise they're left alone. But note that 8th level
fighters usually get pretty good battle potions from Smarter Potions.
- Cult Archers: originally 8th level thief archers, they're changed into
8th level fighters (more hit points and better battle potions).
- Cult Assassins: 8th level fighter/thieves. They get extra hit points
and a stack of Invisibility potions (they'll only use them if you have
Improved General AI installed).
- Cult Wizards: originally 3rd level wizards (in practice), they become
8th level and get Wands of Paralysis (a surprisingly nasty weapon in BG).
- Cult Enforcers: in the original game they're actually listed as high-level
fighter-mages, but they don't use any of their fighter-mage powers. I take
their classification seriously: they are now 15th/15th level fighter-mages,
though with only L5 spells and below, and they use their Wands of Frost.
These guys are very dangerous.
The demon Aec'Letec isn't modified (it's already seriously dangerous) but Tracea
Carrol, previously a weakling wizard (c. L6), is now 11th level. In addition,
the six cultists from whom Aec'Letec draws strength will now defend themselves.
All in all, this makes the final battle with Aec'Letec pretty tough. I recommend
the use of Arrows of Dispelling on your own party to dispel Aec'Letec's Death
Gaze.