How the hell do you kill this thing?
I've tried everything!

Okay you need at least +3 weapons. Things like Lilacor and Staff of Rhynn will work. Cast spells like free action and resist fear before you get him out of the pit, since he stuns and make people flee in terror. Cleric spells like bolt of glory are very useful, and you'll need to lower resistance before you can use magic missile or anything. Also haste, improved haste etc help as well.

Don't know, I just beat it up usually :D

Well, you do need +3 or better weapons I think. Those should be available rather easily in the game. Protection from Fear will help, though I have beated it without those as well. Free Action might help, don't know, never used it as it dies really easily..

Basically give +3 weapons to the tanks and then whack it. Get Melf's Minute Meteors to the caster and pelt it away. It's not that tough at all, when you have the gear..

I changed to the slayer to kill him

That would work perhaps too. I don't really bother with the Slayer form that much, I am sort of a "good"... well OK, not so good but as 'benevolent' at times person, that I do care about the "popularity" factor (Reputation). Changing into Slayer drops it, which though can be good to 'evil' party. And then track the status whether you are "losing it" or not.. Nah [img]smile.gif[/img]

Depends on the level, but I think that around lvl 10 the Balor shouldn't be much of the issue anyway, if you have the gear. Not the ones at least you will run into.

cast loads of spells like prayer and bless and make sure you can cast an outragus amount of lower resistance.