How the fuck do i kill it? I get to the graveyard kill 10+ zombies and then go underground past a door. Theres just 1 level full of rooms and baddies, i kill em all except one boss-like monster.

It keeps saying "Weapon Ineffective". Even after i abuse all of the power-up potions.

Ah you're referring to Brother Toras (according to the walkthrough i just read to find out what you're talking about).

Anyway, i don't know why your weapon would be ineffective, you're sure you have a decent magical weapon right (+1 or +2, what are you using)?
He also uses spells if i'm not mistaken, maybe that has something to do with it. Do you know what spells he casts upon himself?

With consideration to the questions that J had, i killed the bastard.

I levelled up, used Bastard Sword +1, and started hacking. For some reason (he must have had a spell) i had to hit him a few times beofre the "Weapon ineffective" started to go away. Then i just kept knocking him down and killed him.