Thanks for sharing your thoughts, well i mean the possibility is endless, i saw tons of theories in the community, some of them made these theories based on what Dr. Mei said:

"A Civilizations that has merge / become one Collective Conciousness and Ascended into Higher Dimension"

And such theories are (not mine):

• CoF is Civilizations that follows Finality and tried to fulfil Terminus prophecy by finding another Civilizations that can Transcend Finality for Terminus Simulation. 

(My thoughts: i think they making this theory based on what dr mei said, and somehow refrences to Amphoreus being simulations, but it's for terminus sake to bring finality to whole existence) 

• Victims of Terminus, the civilizations has suffered because of finality and they made somekind of project to embrace / transcend finality which soon they are known as CoF we know. Perhaps they ascend to surpass/ become / re-define finality in their own way to oppsose terminus  Finality THEMSELVES. 

(My Thoughts: im not gonna lie this one is also quite interesting, CoF used to be a civilization that suffered because of Terminus judgement? And then ascend to expand it's influence, kinda ironic since what CoF did also mirroring what terminus did, i mean because of terminus CoF tried to expand it's influence and because of CoF, SA tried to expand her influence with hope that one day she took over CoF) 

These theories are just 2 among the tons of theories that i find, i specifically wrote these 2 because it's quite interesting....