- Location
- Earth
I find it extraordinarily unlikely that any of the Dwarfish priests, radical or traditionalist, would make this claim about the (and presumably our) soul for any reason whatsoever outside of a sincere belief that it the truth or a representative of their Ancestors telling them to. Lying about it to save face would be a massive blow to their honor, and one of the core components of their culture that drives us fucking batty is they continue to view that as being of transcendental importance—in my reading, the only reason even Belegar is down with some less-than-directly-honorable stuff is because he views his fulfillment of this oaths as King as being more central to his honor than the specific methods used.
With priests of the Ancestor gods... Well, I'm just not seeing a lever outside of their gods telling them to that doesn't absolutely shred their personal and institutional honor to a far greater degree than Mathilde being amazing and helping them out bunches does.
Basically, if this conclave doesn't end with a third of its members going Slayer, I think it's fair to say that they have a strong reason to believe the dwarf soul claim is the literal truth, and I'm doubting that even the High King could order or connive a different result.
That said, it probably is worth remembering that the dwarfs look at a lot of things somewhat differently. Just as a refresher, this is what we know of their soul beliefs/lore:
There's room for nuance between "the ancestors told me so" and "lying to save face." Plus, Mathilde's soul existing in a legal grey area is terribly appropriate