I am going to start running Mummy's Mask soon, and I was thinking of going into more detail on the concept of the Tripartite Soul (ba, ka, and ib). I'm aware that the River of Souls article at the end of the path says that this is not a real thing, and that basically Hakotep's soul was only tripartite because he believed it was, but I would be interested in changing that if it can be done without contradicting anything else in the game.
Some background: I have a very philosophically-inclined group of players. We once spent nearly an entire session debating the possible afterlife of a thoroughly-dominated vampire (under the control of his vampire creator, but also, by the rules, changed to evil). They're also much more read-up on the rules than me, including one who basically can remember every word he's ever read, so I want to be careful changing anything to avoid contradiction.
We have debated, in the past, what Create Undead does to the soul, and collectively determined that clearly a soul must be trapped even in something as lifeless as a skeleton, because you cannot use True Resurrection (which requires no body!) on someone whose corpse is a skeleton, though you can if it is a bone golem (or anything else other than undead).
I am thinking, when they get to the research portion of the AP, that I will inform those who investigate using Knowledge: Religion of the tripartite nature of the soul, and mention that non-mindless undead tend to have an ib and ba, and that mindless ones tend to have just the ib trapped (or maybe the ka; I haven't decided which is better). This is similar to how undead work in Exalted, which I know at least one of my players will appreciate; it also serves to foreshadow the reuniting of Hakotep's ib and ba and the result thereof.
My question, then, is this: have I missed anything? Is this a silly idea because of some piece of background or system that I've missed or forgotten?
Thank you very much for your time.
