I have killed Gorion with a hacked character. The amulet of full globe of invulnerability is the item that kept me alive, I'm sure. I can't remember now what spells I used against him, but I think it may have been Cone of Cold that finally did him in. I don't think I've tried taking on Tethtoril but I've heard he is even tougher.
I've always wanted to try kicking off an evil campaign by having my character use a Flesh to Stone scroll on Gorion and leave his statue on the steps of the the library as a monument to my character's supreme evilness. Bwhahaha.
You could roleplay it so that one of Sarevok's operatives infiltrates Candlekeep and 'turns' you with the promises of great power, etc. He gives your lowly 0 XP character the items required to knock Gorion off. I've found that if you cast the Flesh to Stone scroll at Gorion before he turns hostile it has no effect. So you would need a potion of absorption to survive his lighting bolts. Maybe a dispell magic scroll to soften his resistance up before turning him to stone.
I'm currently soloing an evil cleric-mage through the game and I would have loved to have tried that but I wanted to solo through the game at least once cleanly.
Now I have to open a game now and see what is required to make Gorion a statue.
[ 03-11-2002: Message edited by: Lemernis ]