Do you think that the Twelve will eventually become major players in the plot?

[Balipu]

Regardless of whether it was truly Halone that appeared to the Coerthans before the founding of Ishgard there has to be some true origin to the mythology of the Twelve. It is very likely the Ascians have used the myths to manipulate people since the Twelve departed Eorzea but I find it unlikely that they fabricated the very source of the mythology.

The game is full of hints and nods to the concept that every myth has a shred of truth in its origins. Something of the Twelve is real, whether they're just people, gods, or something else. Bahamut, Shiva and Phoenix are proof enough of this, and Belias' presence in the SMN quest series suggests much the same for Ifrit.

I'm not saying the twelve ain't real. I'm saying that they likely won't appear in a physical form without the Ascian's consent.