Interesting Question Regarding Voidsent.....

[Cleretic]

You asked to discuss facts, I threw down the facts. I could go into extra math to explain how much of a sacrifice it could be (in brief: I hope you have a least favorite continent on Etheirys), but I see it's not really welcome.

I would caution not conflating 'ancients' and 'Ascians', though. My opinion on the Ancients is actually mostly 'eh', but we weren't really talking about them here. We were talking about the Ascians--explicitly post-Sundering, present-day Ascians, who've gone through a very tragic but very long arc that's ended in them being villains with a lot of impact on the game world; they haven't done a whole lot of good for people living in the Seventh Astral Era, and it's a disservice to the Ancients to claim that aspersions cast on the Ascians are really directed at them.


To get back on the subject, a related subject to the OP's original post: so, is the Cloud of Darkness dead? We know that you can't kill Voidsent on the Source and they'll just snap back to the Thirteenth, but she's the only one of note we actually did fight there. The Thrones talk about us and her as if we killed her, and she's referred to in the past tense, but if we actually look back at the Crystal Tower raids, she didn't die after the fight, and we leave the Thirteenth pursued by her particle beams.

So... did we kill her and they just forgot that last scene? Did she take a while to bleed out? Did someone else kill her afterwards (maybe Obvious Golbez)? Is she still around, but no longer relevant? It's just very odd, because everything's playing out like she died... except for the part where she didn't.

[Alenore]

Zodiark's main reason for creation was aether stabilization. It was capable of other things, but the literal reason it was summoned was to create a stable aether atmosphere, and the second sacrifice was to fuel a stabilization of the world's aether.

That'd be incorrect. Zodiark was summoned to strengthen the aether of the Celestial currents, by harnessing the power of Darkness of "activity and growth". Nor did they wish to stabilize aether for the second summoning, but to seed the star with new life.
That's kinda far from aether stabilization. If anything, Darkness would be the opposite of stabilization, Light would be.

Quickening celestial currents? Totally in its attributions.
Helping life get a headstart? Checks the "growth" part!
Stabilizing the already overly darkness aspected aether of the Void? Doens't seem like it!

Don't get me wrong, Zodiark is a big "aether-to-wish" converter in the end so it probably could, but let's not say it's a task similar to why he was summoned.


I'm also late to the party, but on that part :

So then comes the question of how, and the 'how' is the big enigma. We know that there comes a point where Zodiark is strong enough that he can be awakened and used for this; Hydaelyn in the post-Antitower scene implies this point is after the Eighth Umbral Calamity, but we know that explanation was a bit fuzzy, and the Tales from the Shadows short story doesn't suggest that the Ascians are active in G'raha's future. That might mean that they still had to do more Rejoinings and it's just that the Eighth was the last chance to stop them, or it could mean that they're just off doing something else that Omega isn't privvy to in that story--perhaps that getting Zodiark functional requires a few more steps, maybe something like 'he needs more sacrifices and there ain't enough on the Source, let's go drain the Fourth'. No matter what, Zodiark is eventually an active factor. We know from the Void quests in Shadowbringers' patches that fixing the Thirteenth is possible but slow; that sounds exactly like something you get Zodiark to shortcut, but it also might possibly not be necessary for them to fix it in the first place. We do know that we've never seen any evidence of them trying to fix it though, which lends credence to the theories of either 'they can't right now' or 'they don't want to'.

We don't exactly know that, no. Said cutscene is wrong on many points, and Hydaelyn doesn't mention it'd be over if they rejoin another time. With current lore however, we can suppose that Hydaelyn cannot let another calamity to pass because she knows when Zodiark is supposed to be killed due to the time travel shenanigans.
The Tales of the Shadows story just shows what ascians always do after a "true" calamity: wait for life and civilization to start again, to prime it for another. Besides, when most of the world is scrapping by to even survive, Ascians machination would be the last thing you'd notice. Paragons usually scheme in the shadow and not in plain sight. For all we know, Emet might be building Garlemald 2 while they work on time travel. Nothing supports the ascians using Zodiark at this point.

The Void quest don't tell us we can fix the Thirteenth. Only that there might be a possibility to apply the same method as we did in the Empty, but that we need more informations, hence why the quest revolves around sending a porxie to gather informations to perhaps find a way. Unukalhai landed on no technique, he even says in the final cutscene that it may be years before he knows if he can fix it.

To get back on the subject, a related subject to the OP's original post: so, is the Cloud of Darkness dead? We know that you can't kill Voidsent on the Source and they'll just snap back to the Thirteenth, but she's the only one of note we actually did fight there. The Thrones talk about us and her as if we killed her, and she's referred to in the past tense, but if we actually look back at the Crystal Tower raids, she didn't die after the fight, and we leave the Thirteenth pursued by her particle beams.

So... did we kill her and they just forgot that last scene? Did she take a while to bleed out? Did someone else kill her afterwards (maybe Obvious Golbez)? Is she still around, but no longer relevant? It's just very odd, because everything's playing out like she died... except for the part where she didn't.

They said "bested" and "dispersed", which we saw happen. I don't think Cloud of Darkness took back physical form after that point, even when Doga and Unei stayed behind to sever the covenant. We may have destroyed its physical form if nothing else.
Perhaps the clones actually managed to defeat her for good, or seal her, once we were gone. The fact Nero's corruption got removed seemed to imply that, or that they successfuly got rid of the covenant, but in this case the corruption would be linked to it.