It is because the daystar has the option of destroying the undead, so the programmers did instead of making a insta-kill feature, they just added 1000 points of damage to the daystar spell.
So when you destroy a undead with the daystar spell you'll see a damage of 1000+
ahahha
no
I'm talking about the special ability, its a magic, i don't remeber the name, but is from the cleric list.
probabily SUNray
i don't remember exactly
When the Daystar is equipped, your 'pouch' should be a bright silver. Click on the pouch and you will see a sunburst. If you use this special ability, all undead must save vs death or be destroyed (at a penalty I think)....and this is where you get your 1000+ damage. Of course even if they make their save, the burst does a LOT of damage to undead....and MR and spell protections don't seem to be able to stop it....which makes it the *perfect* Lichkiller.
1000+ damage should kill even Vampires in their gasseous forms.
[url="http://www.sorcerers.net/Games/BG2/SpellsReference/Main.htm"]Baldur's Gate 2 Spells Reference[/url]: Strategy, tips, tricks, bugs, cheese and corrections to the manual.
I always use daystar to immediately kill the lich that guards it. I did it with my solo bard and it was the first thing I did after the dungeon and circus. So it is easy to kill lich's with it
Undead are immune to death spells, the 1000+ damage is just a way to get around that.
When logic and proportion,
Have fallen sloppy dead,
And the White Knight is talking backwards,
And the Red Queen's "off with her head!"
Remember what the doormouse said.