Summoning Undead

I would like a clarification on this as well, do all undead have their souls trapped and twisted in them or is it only "natural" and intelligent? A whole bunch of healers are probably going to be interested on this ruling... What with the focus and all letting them see spirits...

How does this topic work with the question in this topic? www.knightrealms.com/forum/realizing-the...-life-vs-undead.html

They seem to be conflicting, and I'd just like to make sure I understand which one is supposed to be correct.