>>96538882
the white dwarf presented his status as a ancestor god as an objective statement, rather than a belief, so I think it's fair to say he was one

him being the oldest one is highly suspicious as a statement, though
it is very likely that he did have some form of primacy, perhaps he was indeed the first king, as in the role of rules maker and disputes arbiter, it would fit his eventual degeneration into a god of tyranny
while the other ancestors were practically free agents that taught dwarfkind practical stuff like how to forge, how to fight, how to brew etc

I don't remember where it was stated, but grugni and grimnir, and valaya too I guess, were twins, as in created together by the old ones, maybe the dispute of him being the eldest is an overreach coming from the possibility that he was also twin with them and born roughly at the same time