Thanks swcarter for clearing that up, I had thought that posting in that age-old thread would be considered breaking the rules.
Now I have an even better screenshot: I managed to find a way to push Elder Kyusho out of his platform so he fell to the ground, and he'd better get ready for some Wylvan Rage!
Let's see whether anyone else can figure it out - I didn't just mod his coordinates, neither did I cheat in any way, just used the stuff I had available. The good thing is, Elder Kyusho won't teleport back up unless you jump to the ledge where he was pushed down, so you can just go toe-to-toe with him and whittle away his hit points a LOT faster than if you stand on the pillar next to his ledge. There's also a disadvantage to his strategy - he can hit you in melee more easily, but his elven sword doesn't do much damage and there are self-refilling celestial healing crystals to heal the damage he does without using up resources. By the way, I'm beginning to think that the name of my character fits well to what he does - it's German for "there will be 0wnage now".