
Originally Posted by
Ririta
POSSIBLE SPOILERS AHEAD
The concept of the Final Days, as presented in Shadowbringers, is formless, like the Flood of Light. Not an individual, and certainly not "that" individual. As hated as the "space flea out of nowhere" trope is, if we needed a villain with a face, I'd actually respect a last minute, Necron-like deity way more than what we got. Point being: The Final Days is too big to be represented by such an one dimensional, simple life form, and way too grandiose to explain via random newly introduced mechanics. The best way to go with it, imo, would be the same as the Flood of Light. Something that happens, using the laws of nature that we already knew as explanation.
As for the primal: Zodiark himself, while being clear that was not the cause for the Final Days, could very well be the last boss. And its not just him: There were two more characters there to be used, both more developed and deeper than the main villain that we got. Three if you count our Hydaelin, whose goodness was put on check last expansion.
IMO using any of those 4 wouldn't feel like a random pull out of the nethers; that would be doing what FFXIV always did. The way that they actually did it, however, depends on how much you tolerate quite a few things, which includes deus ex machina and a bunch of anime memes.