But here's the thing, G'raha went back in time to change events that wouldn't result in the future still being destroyed. If we had gone back into the past and warned everyone about Meteion then what could the Ancients have done about it? Her sisters were already out scouring the universe at the time we arrived. The Ancients had no means to reach out to stop her, and besides she was made from Dynamis which was an energy that very few Ancients knew anything about. As Ancients they were unable to interact with Dynamis, but as sundered Ancients we could. Zodiark only prevented Meteion from destroying the world by strengthening the aetheric currents, but over time he would've weakened and the aetheric currents would've started to weaken again, then what? Start sacrificing more Ancients to give him the energy required to restabilize the aetheric currents? All they'd be doing is delaying the inevitable at the cost of more souls being sacrificed over time until their race would've been shrunk to too few in number. Meteion herself needed to be stopped and as unsundered we were unwilling to accept strength through tragedy, it was only when we were sundered we faced suffering and a passion for life to strive forward even in dark times which was the answer Meteion was looking for to put an end to her song of oblivion. All the other worlds her sisters visited failed - they either wiped themselves out in conflict, suffered endlessly to their deaths, or believed that life was not worth living and gave up.