They could be a people who easily changed their allegiance. Ocarina of time is a good point. We see how easily some will quickly turn from enemy to alie. They may be the same way with their gods; worshipping whatever individual seems strongest, or conquers them.
No, just have them written by the creaters of the games, and some how influenced by future games. That is a wish worth making.
Could Oldalwa be a "false" god?