Primordial Gods
Primordials
The primordial forces are Light and Darkness. Vital energy emanates from the Light and filters its way down through the various realms, bringing life as it comes and death as it goes, until it reaches the Darkness that swallows it. The three primordial gods—the Wellspring, the Weaver, and the Worm—are associated with that flow of vital energy. They are the core that keeps the living universe running.
The Old Way
The Old Way is not a unified or codified religion, but a set of folk traditions. In fact, the name "the Old Way" is an exonym used by followers of the Church of Light or the Way of Darkness. The existence of the primordial gods is acknowledged by most people, but they are not actively worshipped anymore in most places. The worship of these "nature gods" of life and death are seen as a primitive heathen practice which has been supplanted by the "civilized gods" of the Church of Light and the Way of Darkness. Critics of the Old Way say it simply celebrates the fact that "you are born, you live, then you die" while the civilized gods tell you how you should live.
Rural villagers in the human kingdom of Almarune and many of the Twilight Kingdoms still follow the Old Way as well as scattered groups of ghuls around the Cruachin Rim, but it isn't the dominant religion anywhere except among the wood elves of Brennyssor. The Old Way is outright banned in Aquilan.
The rituals of the Old Way consist mostly of making small daily offerings to the gods, such as throwing a bite of your food into a fire before eating a meal or spilling a bit of liquid on the ground before drinking. Nature spirits of animals, plants, and places are also respected. Hunters offer a short funerary prayer over the body of an animal they kill before dressing the carcass; fishermen say a prayer of thanks to the river, lake, or sea when they pull a fish from it; and, farmers make offerings to the spirits of their fields during planting and harvesting. Sometimes these practices are combined, such as when farmers slaughter a pig or cow for a harvest celebration. They offer a prayer of thanks to the animal then pour its blood on their field as an offering to the spirits of the fertile earth.
One practice of the Old Way has survived because it is not seen as a pagan tradition, but simply as "best practices": the near-universal practice of wearing bells on one's clothing or attaching jingling charms or chimes to equipment and buildings. Every warrior's weapon has rattling rings on the back of the blade or a bell dangling from the pommel. Bells ring as they dangle from the peaks of hoods, the brims of hats, or the toes of shoes. Even the poorest house has at least a set of wind chimes.
Followers of the Old Way do it to keep away evil spirits. Others do it because that's the way things have always been done and it would be strange not to do it. Some followers of the Church of Light or the Way of Darkness know their original purpose but most continue the practice of wearing them out of nameless superstition or social pressure and have made up a wide variety of rationalizations for these decorations: "the sword rings aid in parrying", "they can distract an opponent", "the pommel bell keeps your weapon from slipping from your grasp", "the dangling bells around the brim keep flies away from your face", and so on.
Only thieves and assassins forego the wearing of bells and when they do, others don't always notice their lack of bells but find their presence unsettling because "something is off".
Behind the scenes: The Old Way is basically a mishmash of "European heathenism with no gods in particular" and Southeast Asian folk religions that I experienced in Vietnam and Thailand when I lived in Saigon for ten years. In Vietnam, the god of the fertile fields who was offered a pig or water buffalo sacrifice was really just called Thần Đất or "Earth God" and I see the Thai practice of building little "spirit houses" outside a building for the land spirits displaced by the structure as a feature of Brennyssore architecture.
The bit with the bells was just something I made up while hearing jingle bells at Christmas time and watching a kung fu movie featuring a Buddhist monk's staff with rings and a fighter with a 9-ring sword. I thought that would be a cool detail for character descriptions. Almarune and the Twilight Kingdoms already have lansquenetesque warriors with elaborate brigandine coats of plate and slashed sleeves. A few jingle bells would be the cherry on top of that puffy sleeved sundae. I also like the idea of adding a bit of whimsy to an otherwise badass character, like a ronin with an eye patch and a ragged dirty kimono but with a cute little bunny rabbit netsuke on his belt. Or like the Ravager leader Yondu in Guardians of the Galaxy: "You got any other cute little buggers like this one? I like to stick 'em all in a row on my control console."
Druidism
Druidism is the name given to the faith of the Gelts, the iron age human tribes of the plains of Agored Bhaith, after the Druids, their priestly caste. Druidism is focused primarily on the Wellspring and the Worm, called Light God and Dark God respectively, as the main deities. The Elemental Sovereigns are also venerated as Earth God, Rain God, Fire God, and Sky God. The six gods of Druidism have both masculine and feminine aspects and are treated as divine mothers, fathers, brothers, or sisters at different times of year or during different ceremonies. For example, Earth God is most often "Mother Earth" during planting and harvesting of crops, but can sometimes be "Father Stone" or "Brother Iron" when making tools and weapons or "Sister Clay" when making pottery or earthen walls.
Behind the scenes: Druidism is based on the druid character class (which has very little to do with actual historical druids) and early Slavic paganism with the serial numbers filed off. Perun, Veles, Belobog, Chernobog, Mokosh, et al have been cut down to six core deities and Dunaia, Cnaw, and the Elemental Sovereigns have been slotted in to play their roles in the pantheon. The Gelts are a "barbarian smoothie" made by blending iron age Germanic, Celtic, and Slavic peoples, but based more on the stage pageantry of folk metal bands like Heilung and Irdorath, than on archaeological evidence or academic sources.
Dunaia the Wellspring
Dunaia dwells in the Luminous realms where she gathers and focuses the life energy from the Light and directs it into the physical world to create new life. She is a Gaia-like earth goddess of fertility. She is more than just a goddess of mothers. She is the mother of all and constantly gives birth to the world.
Dunaia is still actively worshipped by mothlings, silklings, garou, and goblins, but among the former imperial peoples (elves, dwarves, and humans), she is only worshipped by the wood elves of Brennyssor and in isolated rural human villages (and, of course, she is worshipped by the Gelts who were "barbarians" during the time of the empire).
Behind the scenes: The name "Dunaia" is a portmanteau of "Gaia" and "dun" as in the The Book of the Dun Cow. It's pronounced "dune-ai-a" or "du-nai-a" because "dun-ai-a" sounds too much like "denier" in a non-rhotic accent.
Mahkeh the Weaver
Mahkeh is a faceless, genderless deity that dwells unseen in the Tellurian realm. If Dunaia is the mother of the world, Mahkeh is its midwife and father. It gathers the four elements and combines them in myriad patterns to create the inanimate matter of the physical world. It also shapes the plants and creatures of the world and brings them to life with the vital energy Dunaia pushes into the world.
Mahkeh is a personification of the natural forces that shape the world, but that personification is not very personal. Both the followers of the Old Way and the Druids focus on the Wellspring and the Worm and largely take Mahkeh for granted. Dunaia brings life to the world and Cnaw takes it away, but the significance of Life and Death overshadows Mahkeh's contribution to holding the world together in the meantime. However, there has been a recent interesting development in major cities: there are rumors of mystery cults of Mahkeh forming among engineers, alchemists, astronomers, mathematicians, and other natural philosophers seeking to unlock the secrets of how the physical world is put together.
Behind the scenes: Mahkeh originated as MHKH, a sort of vampiric tetragrammaton. I don't remember where I got it, but I've used it many times over the years whenever I wanted to have a weird cult that was into mathematics, weird symbols, and sacred geometry instead of gory blood sacrifices.
I wanted to have a mystery cult arising among the Moon Shadows setting's nascent enlightenment thinkers, so I fell back on my old standby, MHKH. Then I realized the Wellspring and Worm were basically like the Wyld and Wyrm from "Werewolf: The Apocalypse" and I was missing a Weaver, so I decided MHKH would be Mahkeh the Weaver to complete the primordial trinity.
Cnaw the Worm
Cnaw, the Devourer Worm or simply the Worm, is the god of death and decay. If Dunaia is "Mother Nature", then Cnaw is "Father Time". Death is something that every mortal creature has to face. It is a universal experience, but strangely, Cnaw is portrayed in a great variety of ways. He is a relentless hunter that tirelessly stalks his prey and absolutely will not stop. He is the grim reaper who comes to cut you down whether you are ready or not. He is a gentle gardener who tenderly harvests his crop at the perfect time. He is a merciless thief of joy and a merciful soother of pain. He is a humorless accountant tallying the dead. He is a cheerful jester who takes all your troubles away: after all, every skull is smiling.
Cnaw is worshipped by followers of the Old Way and the Druids. Followers of the Church of Light or the Way of Darkness do not worship him per se. They have no ceremonies or rituals dedicated to him. However, his images remain popular as apotropaic icons or memento mori. His devourer form, a coiled eyeless serpentine thing, is a common symbol on shields and armor both to ward off death and to intimidate foes. His reaper form, represented by a skeleton (or more often just a skull) with a sickle and spade, is often touched for good luck along with a short apotropaic invocation like "Not today, Worm!" Many people hang a sickle and spade over their doors to touch it for good luck when coming and going.
Behind the scenes: The name "Cnaw" was just the word "gnaw" with a K sound in place of a silent G. He is inspired by the Wyrm from "Werewolf: The Apocalypse", the Devourer from "Iron Kingdoms", Poe's "Conqueror Worm", and a thousand medieval drawings of the Grim Reaper and the biblical pale-horse-riding Death. Originally, he was a more bestial god of destruction and chaos, but over time, I started presenting him more as the steady decay of entropy. His more savage and chaotic aspects were transferred to the dark god, Fel.
The Source
Rather than worship the primordial gods who direct the flow of energy from the Light, through the Material, and to the Darkness, some people direct their focus to that energy flow itself. They call this energy flow "the Source". Some devotees gather in monastic orders for training and meditation to tap into the Source. The most devoted unlock phenomenal psychic powers. The various orders take different approaches to using the Source. Some tap into the light side as life energy flows into the world from the luminous realms while others tap into the dark side as life energy flows out of the world into the tenebrous realms. Some attempt to actively harness the flow and bend it to their will, while others passively ride the current and use the whorls and eddies of energy to their advantage. Many of the orders of Source adepts get along, if begrudgingly, but sometimes philosophical and ideological disagreements spill over into sectarian violence.
Behind the scenes: It should be obvious that the Source is an analogue of the Force from Star Wars. I like psionics in theory but I usually dislike how they are implemented in fantasy games. I wanted something more mystical, like the Force, but less binary.
I'm irritated by the Dark Side being an equal-but-opposite power in Star Wars. Nobody ever said "Light Side" in a canonical source until after Lucas sold the franchise to Disney. It was always just "The Force" and "The Dark Side of the Force". There is no "light side" or "dark side" of the Source as separate things, just like "upriver" and "downriver" are the same water seen from different directions.
The non-binary nature of the Source lets me have a greater variety of Source adepts than just Jedi and Sith equivalents. Groups of source adepts are more like rival schools or sects in a wuxia kung fu movie or a jianghu novel.