I want to clarify things because I my memory/understanding of the story is hazy at best.
We are introduced to Meteion who is Hermes's creation, who is an Entelechy, meaning she is sensitive to ambient emotion just like the flower Venat gave the WoL.
She can interact with Dynamis, a form of energy derived from emotion. We know that Dynamis is counteracted by aether which is why Zodiark was summoned to stop the influx of Dynamis to prevent The Final Days.
1. During The Final Days of the present, the influx of Dynamis caused those with the most despair and sorrow in their hearts to transform into Blasphemies. Is this the same when a person receives an influx of a certain type of aether like how light turns those with too much into sin-eaters?
2. Why was it these negative feelings specifically? Is Meteion specifically channeling "negative" Dynamis and using that against living beings because they'll transform into a Blasphemy as a result? Would the same happen with "positive" Dynamis? OR, is there so much negative energy, that because of Dynamis, they transform? Like Dynamis is amplifying the emotion that's already present, which just so happens to be negative.
3. Why did Meteion suddenly resolve to end all life on Etheirys? Is it because she "transformed" just like the others from the influx of everyone's cries for salvation from life? Or did she just decide to go rogue regardless of anyone else's opinion? Regardless, Hermes obviously didn't mind as he already doubted society due to how they treat creations "unfit" to live. Meteions findings only amplified his feelings.
4. What exactly is the Endsinger? It isn't Meteion because she was cured after being reinvigorated with the Scions' hope. Is it her sisters?
I guess Meteion is a flawed creation. From what I gather, the despair she encountered as an Entelechy caused her to go nuts and want to destroy all life.