Paula
It's sending, not sender I think. Anyway, that encounter is near enough
to the start of the game that I doubt you even need magic weapons (I
could be wrong.) I played the game through twice and remember that
battle being a bit tough, but not too bad. If you want to be a bit
gamey, lure the skels away first so you can fight him alone. Then cast
chant, prot. evil, and such on your best fighter and carve him up.
Is Mirek the brother of the guy who was yeti chow? If so he hangs out
in front of the pottery shop.
That is because swords or slashing weapons are ineffective.
Use a blunt instrument(mace,club,etc) to take him down.