Well, I don't have soulsuck and don't use magic on my character very much. The easiest way to beat him, I found, was just throwing my Purple Sheild up and blocking his attacks. This leaves him stunned for long enough time for me to get behind and backstab him. Not as quick, obviously, but after a few minutes I can take him down. I just have to bring him inside the tunnel cause I get fighting him outside and he was falling off the cliff, lol.
My magic and intelligence are only high enough to carry 2 spells each. Would using Soulsuck even work in a case like this? Do I have the stats to use it effeciently?