Well, there's one or two of those things on the way up the mountain. Why not hit a few and see what happens?
Though, in retrospect, I don't call it cheating to say that Valdis can not be beat by conventional means. The game designers were a bit narrow-minded in forcing people to win the battle they way they wanted it won. Though the cinimatics that come from the final battle make it worth it
~Jessy
PS If you really want the way to kill him spelled out in detail, follow this link
http://www.gamebanshee.com/dungeonsi...inalascent.php
That's from this site's walk-through section.