On Dynamis and Ancients,

Originally Posted by
Fenral
MYTHS!
Venat's whole plan (which we technically gave her) had to do with making us more resilient against Dynamis, otherwise the entire expansion comes apart at the seams. The Endsinger was pretty focused on doom and despair (black Dynamis), which led to the Ancients involuntarily manifesting their nightmares via creation magicks, but we don't really know what would happen with large quantities of the other kinds of Dynamis. (But we do know it has different colors thanks to the Elpis flower.)
Though, with that said, the Sundered become monsters directly under the influence of black Dynamis (even though that always seemed so much worse), so maybe the current state of the Twelve is actually a result of their sundering.
But I'm just spitballing without proper citations, as usual.
Ancients were almost immune to the effect of Dynamis. And sundered people absolutely aren't more resilient to it.
The Song of Oblivion only affected Ancient creations, and not Ancient themselves, because of how aetherically dense Ancient were ; only their creations were twisted. But sundered people are absolutely affected by it, and they can use Dynamis to some effect (for instance, when they pray to you, Zenos and the WoL having a huge Dyanmis buff during the final fight, etc).
Hermes even mentions the fact that Dynamis barely interacts with them, due to how aetherically dense Etheirys is. This is also why Meteion thinks you're an entelechy when she first sees you: your aether is very thin, which is a staple of entelechies.
Venat sundering us had to do with us getting in touch with our emotions and despair, so that we would be able to face Meteion head on and still be able to say "forge ahead" and mean it, to reuse their term, despite our world being on the brink of destruction, our friends turned to Dynamis, etc.

Originally Posted by
Iscah
I thought it was that Ancients were un-vulnerable to dynamis under normal circumstances, which is why the others couldn't trace Meteion after she vanished, but we could.
Hydaelyn had the location of Meteion the whole time, thanks to her tracking spell. What she didn't have was a mean to get there, and who to send to Ultima Thule.
Which is why she entrusts us the coordinates and had the Loporrits be all interstellar-travelish.