Quote Originally Posted by Kesey View Post
It's brought up a few times in ARR by the Ascians to show how close they are to realizing their goals, but to be clear an 8th rejoining just lets Zodiark out of the moon. And the alternate timeline clearly represents itself as being in the middle of an apocalypse even if Zodiark isn't seen. Also the passage of time seen in alternate future is explained too, because the summoning of Zodiark is just a delay to the end days and not an actual solution to the end days. The Ancients that follow Venat and summon Hydaelyn explain this.

So most likely the chain of events are as follows: 8th calamity/rejoining is achieved, Zodiark comes out of the moon, Zodiark causes a world of chaos because he can rewrite the rules of existence, because Zodiark is a primal and rewriting consumes aether he drains the star of aether (this is the apocalypse and takes place over a long period of time), the lack of aether leads to the final days (albeit not immediately).

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The 8th rejoining world was apocalyptic because there had just been a rejoining. They do tend to be rather calamitous events.

I don't think we can really be sure that Zodiark passively consumes aether like current primals do either. Hydaelyn was created using much the same method and has been knocking about for several thousand years seemingly without causing any aether related issues.