>>3836804
It's believed that prokaryotes were the first lifeforms that emerged from the "primordial soup"

In FF16, Ultima's race was also supposed to be the first life on the planet. Chrono Cross did a similar idea with the elemental dragons but admittedly it's a fuzzy concept because the story feels rushed and unfinished at the end with some nonsense about planets as zygotes.

Ultima changes the sky purple as part of "Primogenesis". It's basically channeling Aether into the sky to flood the planet and turn everyone Akashic. Somehow aether erodes people's minds or wills, leaving them empty vessels for Ultima to possess. Genetic transfer, such as Ultima fragmenting it's eikon powers, is something bacteria do. I believe Ultima was depicted with a blue "spirit" body, because it was was analogous to Cyanobacteria.

This concept is likely jumping off of FF15's starscourge, a parasitic plague or bacteria that mutates it's hosts.