It seems to me that, though there are a number of exceptions of course, fantasy settings tend to have polytheistic religions. Also, in those settings that have nonhuman inhabitants, there is very seldom much if any religious crossover between humanity and the other species. Humans generally have one or more pantheons of gods (or occasionally just one god for all humanity), and each individual nonhuman race tends to have one god (or a discrete and separate pantheon) all to itself. Fantasy settings also tend to have a lot more henotheism than is evidenced in earth’s history as well, but that’s a separate discussion.
I don’t know that I buy that, but will detour slightly on the road to why. If the different races’ societies are highly segregated from one another it does make some sense. When our world’s governments consisted of assorted independent city-states, each individual settlement often had had their own state religion and often a god-king (like the Pharaohs) or king-priest (like in Sumeria) figure. Culture and religion were basically equivalent at one point. Many hispanic Catholics and various middle-eastern Muslims may try to tell you that it still is, though the latter will have to carefully hide the Zoroastrians, Coptic Christians and the Baha’i as they say it and the former will have to ignore Santeria, Pentecostalism, Mormonism and more.
As communication and mixing of cultures increased, syncretism really got around. Cultures borrowed one anothers’ gods and religious practices from a very early period on. The spread of Dionysus-worship in Greece and later the Olympian pantheon’s adaptation (and merging with Etruscan deities) in Rome is a good example of this sort of thing. Let’s also not forget the spread of the mystery cults around the Mediterranean as well. Plus, this neat and tidy religious arrangement that is seen in most fantasy settings doesn’t even come close to dealing with the religious situation in medieval China. Then, as societies grew and increasingly mixed, individual religions tended to co-opt, absorb and murder one another in the streets. Witness the spread of Christianity, Islam and Buddhism across the world.
So back to fantasy settings. I decided that I wanted a fantasy setting where human and nonnhuman societies had largely become semi-integrated, and I wanted the religious arrangement to reflect that. So I decided that the primary faith of the setting, Sentierism, would not only be monotheistic but would be mostly general across the continent. Sure, there would be holdouts preserving the ancient religions that Sentierism had supplanted and often absorbed, but by and large everybody that was part of the main civilized societies would by default be assumed to be a member of this faith regardless of species. In fact, the faith’s founder wasn’t human at all, but one of the pale and arboreal alanir.
Just as Christian missionaries cheerfully (and often condescendingly or even violently) preached to the “savages” in the world around them in our world, the early alannic Sentierists saw no reason for their faith to be restricted to their own select group: they felt that they needed to go forth and convert all peoples… and they made a manful effort to do precisely that. As things stand in the setting now, they have largely succeeded at least within the confines of the continent of Occida. At its edges we have a similar arrangement with the spread of another expansionist faith, but I’m not going to get into that right now.
So, while Sentierism itself is sometimes-sharply and sometimes-blurrily divided into competing sects, those divisions are doctrinal and administrative rather than based on the species of their adherents. While it’s true that a lot of alanir support the Archonic Restoriationist or the Reformist movement, it remains a fact that there are still quite a few of them serving as bishops, priests, monks et cetera within the Great Church as well. The pragmatic Durgans tend to be friendlier to the Great Church because of its stability and its general dominance in the regions where they are most numerous, but again there is no one “Durgan Sect” of Sentierism.
Which leads us to the almost-exception that proves the rule: the fomori. The fomori are a nomadic and tribal people that are not only segregated from the other three, but they are often actively driven out and persecuted, even believed to be fleshly demons of a sort. They do have their own religious practices… except there isn’t one monolithic defining religion to which all fomori subscribe. The term that I have used for the mishmash and highly varied religion that this fragmented people follow is the catchall term “Fomorian Folk Religion.”
The fomorian folk religion is something that would likely confuse many of those outside the traveling fianna of the fomori. It combines many sentieristic elements, beliefs and practices alongside a more shamanic tradition of venerating spirits, their own fey cousins and the Lords of Winter themselves in varying degrees and extents. You could call it the setting’s answer to Vodoun or Santeria, in a way, since it often merges saints, angels and Autumnal spirits into a pantheon of sorts. Sometimes the God of Sentierism is held up as a high god presiding even over the Courts of Summer and Winter, and sometimes he is not, and in other instances is still revered but held to be in his own and entirely separate celestial hierarchy. It’s a syncretic mess that has come of the nomadic and tribal nature of the fomori, and from the fomorian practice of taking in the Lost that flee from human, alannic and durgan society and thus absorbing elements of the beliefs of surrounding peoples. In previous times, there was some effort to send missionaries to the fomori but this tended to end badly for the missionaries in question and eventually the practice was abandoned. However, the teachings of the Church have through these early teachers’ efforts in part but mostly through cultural contact and osmosis penetrated even to the outcast fomori.
So that’s what I decided to do with the religious landscape of Occida.