RE: Soulfire
I read the quote like this:As in: Soulfire serves a similar, opposed function as Hellfire (which is the 'yes'-part), but unlike Hellfire it is power within you, used and controlled by you for your purposes.
And compels would be similar to Harry's exhaustion after unintentionally blasting those RCVs and Bob remarking how his soul was shredded because of it.
That's Bob talking about what it's used
for. And it still ignores that Bob says right before that it's from "the other place." He explains how it
functions differently, saying that it does different things in a different way from Hellfire, but the fact remains that Harry can only use this power--at all--because he got on the good side of an Archangel (and, by extension, the White God).
If you can only use the power because a super-powerful being gave you the ability to, that makes that super-powerful being the power's sponsor.
Think of it this way: Harry's magic is like the Blue Beetle: He owns it, he maintains it, he pays for the gas, and he can use it however the heck he likes, at no cost except personal, because it's his. Soulfire would be a rented or leased car--Harry is still paying for the gas in the tank, but the car isn't really
his--there's a contract, certain things he'll be willing/unwilling to do because of that contract and the debt he still owes to whoever he's renting or leasing it from.
As for Kemmlerian Necromancy, I'd say the agenda might resemble what Kemmler was up to...whatever that might be.