First, Thanks for the tips on my last post. I still can't get past the Demon Knight. I am attempting to get down the stairs behind him and every time I am getting hit by fire killing my fighter. I am a Level 7 fighter with -5 armor. I have used Protection from fire and Fire resistance, and have hit him with Wand of Lightning and fire. I also used arrows of biting. Any tips would be appreciated. Thanks

But are you talking about the FIRST time he appears just right after you arrive to Durlag´s Tower ?? If so, he always throws the fireballs in the same direction (he doesnt aim to your party members), so just run away after you talk to Ike, and the fireballs wont hit you. You dont have to kill him now, be patient ;)