Shadow Lich? What to do?

I've killed a couple of liches in identical looking areas and have gotten arms, legs and golden torso of them. What is this all for? I also stumpled into a planar area (bridge district, by the tanner)or something like that with another lich who kicked the ever living stuffing out of me, so needless to say, I'm waiting before me and my rogue stone go back there! Any ideas? Also, is the placement of artifact pieces random or predetermined?

[Hawk]

Firstly, I'd like to thank a few people on this board for helping me with this too.

You have stumbled upon a good challenge. In the Docks area there is another house like the ones with the arms,legs and torso. This one has a head. I won't tell you where it is, but try every house. The door is locked, and trapped. That is as much as i am giving away. Oh, and when you do get there, it is possible to complete the quest.

[Memnoch]

Placement of artifacts and items with unique histories are fixed.

He's also stumbled onto another good challenge in the process. The rogue stone doorway is the entrance to the secret lair of the Twisted Rune. I don't really know what this whole Twisted Rune thing is supposed to be, but they consist of a lich, a beholder, an unarmed thief (heh), a vampire and a sorceress. I'd reccomend luring them out one at a time. You can lure beholders by throwing a fireball in their general direction when they're offscreen. Good luck.