Here you can find what the "Void" means traditionally in the Final Fantasy series. As far as ARR is concerned, though, the Void seems to refer to some kind of alternate reality where there is no matter. Creatures emerging from it most likely gain a physical form when entering a material realm, as otherwise the term "Void", which sugests nothingness, makes no sense. Though it is possible that Squee was thinking of it as just a generic hell, but that's unlikely.
There's no hard lore about it, though what is true is that Squee uses it as a generic fantasy hell as far as summoning creatures from it is concerned. There's no word on how to contact them in-game. Though I remember a FATE in Northern Thanalan were a cultist lets herself be taken over by a succubuss and ends up taking its physical form.
There's no hard lore about it, though what is true is that Squee uses it as a generic fantasy hell as far as summoning creatures from it is concerned. There's no word on how to contact them in-game. Though I remember a FATE in Northern Thanalan were a cultist lets herself be taken over by a succubuss and ends up taking its physical form.