Yo Shien, admittedly I didn't read the entire post you wrote (nor did I read much of the discussion as a whole), but while skimming I saw your question over why a soulless body would die. I'm hoping I'm on the same page here, suspecting that you refer to what happens to a body after, say, the Withering or theoretical maximum magical exhaustion? If so, I recall Jack stating that a body's soul always determines the best possible condition for said body (but not the worst possible), so wouldn't that mean that a body without a soul (or a depleted/dead soul, whatever) would technically have a best possible condition of "dead"?