The official pantheon of Quinternia includes all gods that are signatories of the Divine Compact, a thousand-year-old agreement written by Ahasitari. Those that have signed the Divine Compact agree not to interfere directly with mortal affairs, and in exchange gain the abilities to both receive worship from mortal followers and the right to grant divine clerical spells to their most devoted worshippers.
Those gods who do not participate in the Divine Compact, whether native to Quinternia or not, are considered “dark.” Dark gods all either rejected or were not invited to sign the Divine Compact, relegating their followers to cult status. This category also includes various other powerful entities that might seek to control mortal souls, such as demons, devils, the Fey queens, and other cthonic Far Realm entities, as well as followers of deities not native to Quinternia. One may find dark priests serving these divine pariahs, but the others tend to imbue warlocks, rather than grant cleric spells. Regardless, the nature of the Divine Compact mostly hedged out influence from dark gods, and virtually eliminated influence from gods not native to Quinternia.
Fifty years ago, at the end of the Second Eidolon War, that changed. In a great cosmological upheaval created by the defending forces’ victory, the unique nature of Quinternia shifted. The Divine Compact partially metaphysically unraveled, no longer preventing non-signatories from gathering worshippers, but still preventing the most direct divine interference. The impacts of this are still unfurling.
Religious doctrine and legend both agree that most of the native gods of Quinternia are former mortals and adventurers whom have achieved divine status through heroic effort and sacrifice, inheriting, stealing, or winning their Apotheosis from deities that came before. Some scholars have even theorized that older gods that do not have a documented mortal life and apotheosis are simply so old that those records are lost.
Almost four centuries ago, several deities died, with new ones taking their place, during the Reordinance of St. Dumon. The Great Devourer, a titan of unimaginable power, arose ahead of its normal cycle to threaten the world with oblivion. In the battle, multiple gods fought against him and were devoured into oblivion. At the same time, the mortal hero St. Dumon slayed the titan with a weapon forged specifically for that purpose. Afterward, several of St. Dumon’s adventuring companions were offered Apotheosis by the surviving gods and accepted, joining the pantheon, though St. Dumon himself famously refused, remaining mortal.
The gods listen to prayers and invocations of their names, and will sometimes (but not always) choose to provide their favor via more direct means, be that in the form of a sudden stroke of favorable circumstance or significant omen. It’s said that, ages ago, they took more direct interest in the affairs of mortals, but now, with the Divine Compact, they stay more removed from the Material Plane, only communing with their most powerful and loyal servants.
It is also said by great theologians that a great, overarching creator deity rules over all the gods and creation, though if such a being does exist, it is far enough removed from the Material Plane that mere mortals rarely ever hear a rumor of it. If the Pantheon knows anything about it, they're not telling.