Q: Venat had good intentions and her plan worked out in the end. But as a result the world was Sundered and most of the Ancients suffered. Was Sundering the star really the only way to save it?
A: This is a question that I consulted with Nacchan (Natsuko Ishikawa, Scenario Writer of Endwalker) to come up with the answer so it will make sense when we explain it. At the very least, as Y’shtola theorizes, Venat believed that the Ancients, being so dense in Aether, could not control Dynamis. So she thought they could not have stopped the Final Days and its source. So you know there were other Ancients who thought summoning Zodiark would solve everything but she saw that summoning Zodiark and using it to deflect Meteion’s “Despair Beam” and thought, “even if we were to do this and keep going as we are the rest of the Ancients will probably be unable to change as a people” when she’s looking at Hermes, or “we will always be our own undoing”. If you look at the dungeon, “The Dead Ends”, at the very end there’s a boss called Ra-la, and that’s sort of our vision for what probably would have happened to the Ancients if we just let them continue as they were.
So for that reason, she chose to Sunder the star to dilute mankind’s Aether so that someday they might be able to use Dynamis and to fight back against despair and the Final Days at the Source