[Tiresius]

I would appreciated any advice reguarding killing this thing. I had just finished playing and i killed the demogorgon...but by then all my meat shields were dead and the two other demons killed me. My party consists of roughly lvl 22 characters:

Sorceror
Keldorn
Sarevok
Viconia
Edwin
Jan

Before i ran down there i summoned 5 skeleton warriors (my friends advice) to take most of the damage from everything. My character had a contingency of 3 Wiltings to go off on sight as well as a spell trigger with 2 lower resist and a greater malignon. Likewise goes for Edwin (both trigger and contingency). right off the bat i get of 6 Wiltings that puts him down to berely injured. Then Jan continually casts breach, Edwin alternates between pierce magic and Wilting, And I Alternate between Ruby Ray and Wilting. Since i dont really know what all of the protection removals do exactly or what all of the protections do i just try to cast everything.

As everyone is chopping away i get the demogorgon to badly injured when all my skeletons just die with the finger of death animation thing (i assumed it was death spell) Then we continues fighting/hacking/casting and the demogorgon dies HURRAY!! Both my tanks were poisoned and dieing quickly however. Viconia couldnt cast greater resoration fast enough to save them. So I began to summon new tanks to finish the demons, but before my planetar can get thier attention (and me run away) i am killed. To my distress and irritation i reloaded and gave it another try. I never even got the demogorgon past berely injured.

Can anyone tell me how to modify (or completely change) my strategy? It would be greatly appreciated.