Anybody got any solid tactics for beating this cocky git down to size?

Party composed of Aerie, Jan, Minsc, PC (Mage), Nalia and Keldorn. Levels are approx 15-19, after the underdark so some decent L8 spells available :D

I've never managed to beat him on my own yet, though I completed the Ritual some time ago. All help gladly recieved.

Try to position Jan as the only one near him, protected by Mirror mage and Protection from Magical Weapons. Why? Because his Time Stop is hell if he manages to find an un'buffed character. Breach using Nalia (or Dispel Magic from Keldorn), then dispel using Caromnyr, Breach again if he uses Protection from Magical Weapons again. Use those Wands of Spell Striking (do you have any? If not, then Ruby Ray) to get past the SI: Abjuration. Improved Haste is very important. Keldorn and Minsc both can kill him quite easily.

You can also use Contingeny - PFMW - Enemy sighted with your Mage for the first Time Stop. He has three !
Potion's of Invulnerability, ...

He can also cast 2 (maybe more) ADHW's.

I just beat him with a solo Blade (lvl 40). ;)
Carsomyr is very very useful, then FOA !

If Jan has UAI and Time Trap - use Carsomyr with him !

You can also try (after dispelling his Spell Shield and Spell Trap) - lower resistance 3x, Doom, Greater Malison, Feeblemind !

And then kill him fith your toe

After Feebelmnding him :D

Xen why put that in two posts when it could have easily been put in one?

hmmm...more posts, perhaps?

FOR INFORMATION ONLY:

Just a note of the initial spells he casts... don't bother reading on if you don't want to be SPOILED. I really do mean SPOILED.

You have been warned.

Also include countermeasures to some of the spells.


SPELL TRIGGER
Protection Magical Weapons - DISPEL
Protection from Magical Energy - DISPEL
Improved Haste - DISPEL
CHAIN CONTINGENCY
Spell Trap - Duration 18 rounds.
Spell Immunity: Abjuration 1rnd/level
Time Stop
Protection from Magical Weapons
Protection from Magical Energy
Spell Trap (again) - Duration 18 rounds
Wing Buffet
Spell Shield - Protects against one 'removal of spell defences' spell
SPELL SEQUENCER
Improved Invisibility - 3rnds + 1 rnd per level
Remove Magic - Character who speaks to him
Slow - Character who speaks to him

Other points:

There are several SAND GOLEMS that appear to join the battle. He will use dimension door to appear next to your main character (where possible) almost continuously. Appears to have 3 timestops. He will summmon magical swords quite often (infinite, memorise several death spells).

ummm.... where the heck is this encounter?

Its part of the tactics mod.