Quote Originally Posted by Cleretic View Post
Essentially, every FF game exists as a separate universe within a multiverse, between which is the Void/Interdimensional Rift (the games differ on what exactly they call it, XIV goes for the Rift because it's already got a Void).
The Rift in FFXIV is what separates the shards of the sundered world. There is no confirmation that it stretches further than that – the closest is Omega reproducing things it has seen via the Rift, but between its inability to distinguish fact from fiction and that "things from other FFs" encountered in Eorzea tend to be copies rather than direct crossovers, there's no guarantee that Omega hasn't simply found either similar copies or legends in the other shards.

Of course, there's the question of just how Omega got the ability to interact with the rift when it was built on an unsundered planet, but it's possible that it evolved the ability after arriving on Etheirys.