The Doomsayer is the guardian of an ancient temple of Kozah in the Archaeological Site south of the Lighthouse. This temple is being excavated by Charleston Nib. If the Idol of Kozah is taken out of the temple, the Doomsayer will appear and attack, after a brief dialogue.
The Doomsayer targets the nearest party member with melee attacks, and is quite powerful. Even at level 6, the party member being attacked will need extensive healing and other support (Bless, Protection From Evil, etc.) to survive the encounter.
The Doomsayer can only be damaged by enchanted weapons and ammunition, and is immune to electrical damage.
The Doomsayer appears as a human male fighter and comes equipped with a plumed crest helmet (immunity to critical hits) and Plate Mail; the latter, however, doesn't have any effects on his armor class, as he has a natural AC of -2 that is further lowered by 3 through his dexterity. He wields a flame blade, similar to the weapon created by the spell, that in the classic Baldur's Gate deals 1d4 +4 fire damage and gives a -4 bonus to the Doomsayer's already low THAC0 of 8.
In addition he wears two rings. One of these grants him immunity to a number of status effects: berserk, charm, confusion, fatigue, panic, paralyze, petrification, poison, slay and sleep. The other one creates a field of blur that lowers his already very low armor class by an additional -3 bonus, to an overall value of -8, and adds a -1 bonus to all of his saving throws.
The flame blade and the blur field are dispellable. None of the items will be dropped by the Doomsayer.
In the original Baldur's Gate, Dispel Magic will make all the difference when fighting the Doomsayer: it dispels his Blur and Flame Blade. With fists alone, the Doomsayer's damage is minimized and he is never able to kill, as fists only knock someone out. In the Enhanced Edition, however, dispelling magic has no effect at all on these built-in abilities.
Fire, ice, acid and magic damage spells will work. Lightning will heal him, as he has over 100% lightning resistance. Wands of Frost and Magic Missiles work. Wand of Paralyzation works even better. Also, in case Dispel Magic misfires, have Oil of Speed prepped for one of your main fighters armed with powerful weapons. Note also that ranged weapons can be helpful to halt the Doomsayer just enough to maximize the effect of Web.
While he's immune to the damage of missiles, he's not to their magical component, so Acid Arrows and similar will work.
To disengage, you'll need a distraction, and the best one is probably summoning creatures to keep him busy. Web will work well enough, though he has high saving throws (at least whilst blurred) and won't give up the chase despite being out of sight. You'd probably have to flee the zone and return to disengage combat.
The easiest way of killing Doomsayer is to lure him towards Brage. Thanks to his cursed sword, the captain will turn berserk in the presence of an enemy and will go after the apparition. At this point it's best to quaff a Potion of Invisibility or to hide in shadows (the cart remains can be used to break line of sight), but simply running in circles should also work. Brage attacks only once per round and needs a good roll to hit Doomsayer, but his every hit deals very respectable damage.
IthNal cOR dan osa KOZAH! Rrrackne dall'a osa KOZAH!
- 1:-Speak common, you abomination! I cannot fathom your words!
- Sssstormss shall bring doom to theeee... Idollll so commandsssss... Echtah tuln no osa KOZAH!
- 2:-Speak your gibberish as you will: the end will be the same. Die, you unnatural beast!
- Nottt for theeee to underssstand... neeeed only dieeee while youuu hold... idolll does soo commannnnd... Eltor anSle osa KOZAH!
- 3:-What are you trying to say? Speak, and I shall see if I can help you.
- Hhhellp? Nooo hhhelp for theee... only sleeeep... eternity sleeeeep of one forgotttt... deathh of godsss... idol take theeee wwwwhile you hold... I reclaimmm! Oro lan t'ola osa KOZAH!