....or so the mythology books tell us.
They could totally pull a "Dragon Age" and introduce an entrenched mythology/religion only to have it be one possible explanation for the world being the way it is.
If you haven't played that game, then very early on it presents the player with an explanation for the creation of the world (the Maker) the existence of magic (the Fade) the bad guys (Darkspawn are corrupted mages who violated the Maker's golden city). And all sorts of other stuff about a magic prophet (cross between Joan of Arc and Jesus), etc. etc.
A typical player (like me) would think, "alright, I understand the basic lore now." Only, this is basically like accepting the King James Bible as the one and only explanation of (our) universe. Dragon Age leaves it truly unanswered just how all these mystical things came to be.
And in fact you get this with other games too. The Sacred universe has its 6 gods, well established throughout the land, but the Seraphim are adamant that there is in fact only one.
It's just a possibility, that could be a lot of fun, depending on how much Larian wants to delve into/play around with the lore....