Quote Originally Posted by Veloran View Post
Another note on this point - The Ancients only got the Zodiark plan up and running with the first sacrifice after 99% of the planet had been rendered a desolate wasteland and Amaurot was just about the last place standing. This was the entire point of the second sacrifice, the world was effectively dead and the cycle of life destroyed. Thus they were unable to do anything but use themselves.

Maybe such a thing could have been averted if they had somehow known in advance, but that is neither here nor there.
Indeed. They had emphasised wanting to complete their plan on Zodiark before the crisis hit Amaurot. It's later specified in EW that it moved very rapidly. I believe a big part of that was because of where the fuel to summon him was going to come from and that the sacrifices were forced on them as a necessity given the depleted state of the star.