Foreign Invasion

[Enkidoh]

Also, I recall the whole reason Azdaja was lost in the Void in the first place was because the Allag under Xande had opened massive gates to the Void as part of their pact with the Cloud of Darkness to aid them in vanquishing the Mercaydians (Azdaja flying into it to try and close it from the other side), so I think it's very much a yes that the Void can and will invade the Source if given the chance, especially as many voidsent are reduced to a single minded "consume aether" state due to aether starvation and the chance to consume an entire world of aether is too appealing.

The only reason they haven't since the Allag's days is due to the Voidgates that have appeared after the Allag's fall being generally too small and unstable to let much voidsent through, and even then only low tier ones, and usually singularly, even the one we've just brute-forced open in Alzadaal's Legacy - there are exceptions to that though - just prior to the Seventh Calamity for instance Atomoses were materializing above aetherytes throughout Eorzea, deaspecting the aetherytes and turning them orange, allowing them to disgorge hundreds of Voidsent that would swarm the surrounding area - after Dalamud fell though, they disappeared.

But it remains to be seen if Golbez's 'crusade' is indeed a planned invasion of the Source - definetely the hints are there.