Normad20

I don't know if this has already been posted, but I have a theory about Vax that I think might be new. What if it's a gas giant? Scadrial's Cognitive Realm is made of mist, so it would probably look similar to the atmosphere of a gas giant (I think. I'm a writer, not a scientist). Maybe Ati/Ruin has been to Vax before, and thought that he had appeared there after his death (hence his apparent confusion). I know that there's some scientific issues with living on a gas giant, but honestly, if anyone can write a fantasy novel set on one, it would be Brandon Sanderson.

'"Oh, Senna..." Preservation whispered. "I'm losing this place. Losing them all..."' Is this the part you're talking about?

I'm pretty sure the Death Rattle refers to the Thunderclasts, which are made of stone and have red eyes. Not so sure about the Szeth thing, do you have a quote?