I hit him on the head, until he's dead <img src="/ubbthreads/images/graemlins/delight.gif" alt="" />
He is tough, one technique some people used is to:
<span class='standouttext'>Spoiler : </span><span class='spoiler'>click on the portrait in the room, a door to the south opens with a Healing fountain or some such, fight him near it.</span>