Earthist Religion

Earthism is believed by those who study such things to be descended from the original religion of humans in their lost homeland.
Practiced mostly in the country, it has colourful seasonal ceremonies connected with the agricultural cycle and the sun, and a number of fairly superstitious practices aimed at propitiating small spirits of place such as hearth spirits, stream spirits or the spirits of notable trees.
In Earthist cosmology, there are five concentric worlds: from inner to outer, the body world, the soul world, the spirit world, the world of the honoured ancestors and the highest world. Most people can only perceive the body world directly, accessing the soul world through it, but a shaman's training gives them the ability to first perceive, then manipulate, and finally enter the soul world, and eventually the spirit world. Ceremonies work by increasing the depth and complexity of soul linked to a person, place or object, then attracting the spirits to the pattern so prepared.
The soul world is perceived symbolically and works by relationship and analogy rather than by the rules of the body world. For example, distance in the soul world is not physical distance but relational or emotional distance. Your lover who is a thousand miles away in the body world is right next to you in the soul world. Even relatively inexperienced mystics can perceive these connections between people (though, since the physically distant people look nothing like they look in the body, if the mystic doesn't know both their body and soul appearance they won't be able to tell who the connected person is). They can see if you're lying or afraid or angry, as well.
The worlds are closely linked in people, of course - that's more or less a definition of "people" to an Earthist shaman - so healers can see (and advanced healers can manipulate) the health and general state of the body through the soul world.
How the soul world appears differs between different people, because it's symbolic. However, inexperienced shamans tend to see it rather dimly and in terms of shadows, while experienced shamans see it much more clearly and in terms of light. Who you are looking at also makes a difference: an experienced shaman will seem much sharper and brighter, even to an inexperienced shaman, than an ordinary person.
Shamans are expected to look for potential students, whom they identify by their soul appearance. These are postadolescent boys and girls, who lose their clan name when they apprentice to the shaman. While meditating alone, the student who has properly prepared will be approached by an animal which will touch him or her somewhere on his or her body. The name of the animal then becomes a name of affiliation. A kind of magical picture of the totem animal, like a tattoo but made without ink and raised up above the level of the skin, appears at the point that the animal touched. This is generally taken as a form of guidance on what powers the mystic will primarily develop. The limbs indicate body powers, while the head and torso indicate soul powers. Those marked at the hip or shoulder are likely to be equally strong in both.
The student will train with a teacher of their own gender (usually; exceptions are occasionally made under unusual circumstances) for approximately 10 years, by which time they will be ready to receive their totem animal and go out on their own. Later, in another meditative trance, they receive the revelation of their totem plant, and the image of its leaf, flower, root or other distinctive part appears on their body opposite the animal mark. (It is marked on the left if the animal mark is on the right, on the front if the animal is on the back, and so forth). They add the plant name to their name of affiliation after the animal name, and are considered a full shaman. It isn't necessary to be a full shaman in order to take an apprentice.
Shamans have no possessions apart from their clothing, a single piece of cloth wrapped around them for the sake of modesty (but in such a way as to leave the totem mark visible). In places where water is scarce, they may also carry a water gourd. They traditionally sleep outside, since they have control over their body processes and can keep themselves from freezing even on the coldest of nights.
Earthist shamans are not any kind of clergy. They don't tend to participate in the popular seasonal ceremonies, for example, and when they do they seldom take a prominent role. They are healers, counselors, diviners, holders and teachers of wisdom, celebrants and assistants at life's transitions (such as birth, puberty, eldership and death), and consecrators of important objects, places and people. They are supported by the community, but as professionals who provide specific services at specific times to specific people, not as leaders of a permanent congregation. As in Asterist practice, and probably derived from it, enactments such as marriages are performed by the heads of households or extended families or by community leaders. (Thus, it's particularly difficult to marry without the consent of one's family, at least without leaving the community to go elsewhere, which is what people do.)
The small spirits of place, despite their special connection to a point in the body world, basically inhabit the spirit world, but can descend into the soul world if they want. They can meet the mystics there and communicate with them. It is hotly debated whether they are servants, manifestations, descendants or creations of the great spirits described by the Asterists, most of whom are now acknowledged also by the Earthists, though usually under different names and aspects.
The spirit world is, for humans, uncommunicable and indescribable, since it is a realm of pure being and identity. Shamans believe that by practicing their spiritual disciplines of concentration, renunciation and attention they can come to experience this aspect of reality, though of course they can't say anything about it because words are inapplicable.
When a person's body dies, their soul, no longer anchored in the body world, is drawn towards the spirit world. However, if there is something in the soul world that holds them, they may hang about until it is resolved. If they are very strong or determined, they can cause effects in the body world in pursuit of their resolution. (They're ghosts or unquiet spirits, in other words, and a shaman will generally be called upon to find out what they want so that they can move on.)
The fate of souls which are no longer anchored to the earth differs depending on their history. If the soul is one with living descendants to carry on its lineage, it moves through the spirit world to the world of the Honoured Ancestors, who watch over the community and, through the shamans, communicate with it. "Descendants" means "descendants of the soul", so shamans, who rarely marry, qualify as ancestors if they have trained students and those students are carrying on the lineage, while a man who fathers a bastard child and never knows of it or raises it will not become an Honoured Ancestor. Souls which do not qualify as Honoured Ancestors return in another body to try again. The Honoured Ancestors also facilitate the creation of new souls to send into bodies and eventually rejoin them, having learned the lessons of life; the greater spirits must, however, breathe life into these souls before they can incarnate.
Shamans are believed to have returned from the world of the Honoured Ancestors in order to assist the community, an act of great merit. At the death of the second body, they are thought to begin the transition into the highest world, the world of the greater spirits.