Sundering and specific character questions. [Spoilers]

[Rosenstrauch]

On the other hand, voidsent seem to have no trouble possessing dragon corpses, as evidenced by the sheer number of dragon zombies that tend to crop up. So I wouldn't be surprised if, at the very least, the same was true for Ascians. But I'd wager only an Overlord could possess a live dragon, and the Great Wyrms might be impossible to possess if their souls are as robust as Midgardsormr's.

As for why they've apparently never done it, maybe infiltrating dragon society would be exceedingly difficult compared to the alternatives. Or maybe, as extraterrestrial invaders handed dominion of the star by Hydaelyn, the Ascians simply hated them too much to even consider it. Or maybe dragon's eyes acting as a sort of natural auracite meant they'd get Lahabrea'd if they weren't careful around dragons.

Or something else entirely. Who can say?

[Vyrerus]

I think there is a difference between externally exerting control over a species and actually inhabiting their body.

Not really a compelling argument, all things considered. Though it's obviously true, insofar as yeah, the mechanism for control would be entirely different.

There's what Rosenstrauch said about Voidsent.

There's also the fact that Estinien was able to resist Nidhogg, at all.

Then there's also the fact that dragons are shown to be inferior to Ancients in regards to not possessing creation magic innately, given that Tiamat had to learn it from the Ascians in the form of Primal summoning rituals.

I think I'd chock it up to the Ascians finding a way to control them with neurolinks early on, giving them no need to possess them. Why possess what you can so easily enslave? Especially if it hurts the soul/weakens them.

[Beddict]

Going back a few pages here to answer this:

And where was it stated that the new life Zodiark cultivated/renewed before the Sundering was less powerful/had less aether power than the average Ancient? I see that stated a lot, but I can’t recall where it was stated in the game itself?

It comes from Patch 5.3 with the Convocation Crystals. The Crystal for Emet-Selch reads:

Gone is the brilliant radiance of life, replaced by the sickly glow of malformed creatures. Is this to be how it ends? For we who loved the star with all our being? No. I will not suffer it to be so.

That said, there's a chance he's talking about life post-Sundering. The Convocation Crystals seem to cover quite the range of time, with Lahabrea talking about how they need to rewrite the laws of creation which would be before the summoning of Zodiark, and Pashtarot talking about how salvation came at a great cost which would be after the summoning of Zodiark. Most notably, Halmarut has this to say in their Convocation Crystal:

Behold, my friends.
Embraced by the earth and caressed by the wind, vibrant life flourishes. All is right in creation.

We don't know how gifted Halmarut was at seeing souls, if at all, so there's a chance they might not have noticed how malformed the new life was. Either way, this quote definitely happens after the second Amaurotine sacrifice and before the Sundering. As for Emet-Selch, his quote could be before or after the Sundering. Since he was so incredibly gifted when it came to looking at souls there's a chance he saw the new life created by Zodiark as malformed where Halmarut didn't, or he was talking about the Sundered lifeforms which we know he thinks poorly of. It could go either way.