What exactly do we know as of 5.3 about the sound that was heard before Amaurot fell?

[Alleluia]

I too believe the Ancients and Amaurot have to had come from something. My wild guess is that, since the Convocation seats have the names of the opposing scions of Light of XII's espers, perhaps they once fought the Lucavi like Ultima and the others we see in the Ivalice raid? At her defeat, Ultima proclaims: "I am your mother! I am your maker!" Which is... intriguing.

However, I should note that it was Hythlodaeus I was quoting, for he is qwho mentioned that at Hydaelyn's summoning, "for the first time in history, our people stood divided". Given the Ancients' lifespan, however, and that they were not immune to the fog of ages, I cannot put past them the possibility of having forgot whatever conflicts they overcame to reach their heights.

I just took "our people" to mean Amaurotines, not the entirety of the human(?) species. The Amaurotines all talk like they were the only ancients, but there had to be other cities, other cultures than Amaurot. In fact we know of at least one other city from ambient conversation in Amaurot. Amaurot was just the last city standing.

(Plus, Azem would have basically no job if there weren't other peoples to interact with; no new friends to make and then throw group teleport requests at.)

In that context, to say that Amaurotines, as a people, never experienced a conflict that they couldn't overcome with debate is perfectly feasible. No nation has a civil war until it does, and in theory its possible for them to have always managed to reach a consensus. I dunno how other peoples would have felt about the Amaurotines apparently always "dictating the direction of the star", but maybe they agreed to let them at some point? Maybe that was what Azem's position was made for, to maintain an ear to the other inhabitants of the world from the city that everyone's ancestors had agreed was allowed to decide that stuff.

That could be a very possible event, and now that you mention Jenova we might be onto something because was it not Jenova who caused the Ancients' demise in FFVII? I would assume that Zodiark weaving anew creation might have ended the threat... for the time being. Emet brings up the possibility of it happening again when illustrating the issue with selfless sacrifice and mortals, so it would seem the Unsundered at least were well aware that it could happen again. And if it almost obliterated the Ancients and was only stopped through mutual cooperation, Emet had every reason to worry about what would become of the star if events repeat.

If the Sound was the result of something threatening and damaging the Lifestream, then I would say this by itself puts three names as the best prepared to identify and fight the threat: Azem because it was their role in the first place to locate threats to the star, Emet because of his natural affinity with the Lifestream (to the point he was considered "a denizen of the Underworld") and Hythlodaeus because of his heightened aetherial sensitivity and if the Sound was making the Ancients' creation magicks go haywire he was the Chief of the Bureau of the Architect and probably had a lot of experience in that area. And this of course brings back to the table the original power friend trio, and it reassures me in my opinion that they will be quite relevant for the story's resolution. Something tells me they hold the key.

^That is the theory that I like the best, personally. Its between that and the idea that it was overuse of creation magic, I think. And the story hasn't confirmed one way or another, but given how controlled and seemingly well understood creation magic was, I doubt the Amaurotines screwed up badly enough to get blindsided with the end of the world. Plus, the sound started on the opposite side of the world to the Amaurotines, hence why they talk about losing contact with other cities as the phenomena makes its way towards them.

Also, the sound was causing meteors from space, which is just a weird choice to me. How many people's creation magic going haywire would cause the same identical phenomena like that? And how does creation magic on the ground even do that? I know we've got several instances of meteor spells in-game and meteors being dropped on us by bosses, but they don't come from *actual* space, they manifest within a couple hundred feet above us. These meteor showers were from at least low earth orbit.

When I first played, I thought perhaps the Ancients had reached space, tech-wise, and their satellites and/or stations were falling or something. We have no indication they did or didn't have that, but still, the meteors seem to be originating from beyond the planet, whatever they are composed of. It just feels like an external attack to me.