Of the three kinds of professionals who possess specifically magical knowledge (gnostics, priests, and shamans), shamans are by far the most feared on the plains.
To become a shaman one must be approached by a daimon, a kind of astral symbiote that lives in the Great Light beyond the night sky. This typically happens during a serious sickness or due to a vision quest, or from some other stressful circumstance. The daimon offers to bind with the would-be shaman in exchange for their service towards the daimon's goals. Refusal is possible, though daimons tend to approach at moments where it is extremely unlikely. Once bonded, there is no "going back" or stripping the daimon from the shaman, except by death. The daimon, until it bonds with a person, cannot affect the material world directly.
Daimons are effectively immortal, and once bonded serve as the fetch and patron spirit of the shaman, teaching and aiding them in the binding of the spirit world in exchange for tasks. These tasks may involve the following of taboos and performance of rituals, but just as often they are specific, often dangerous changes to the world. Daimons may be good, or evil, but just as often they are inscrutable and alien, even to their hosts. They appear to possess a kind of dominion or authority over other spirits, and the most common kind of task they demand of their host is binding and compelling other spirits to stop interfering in the world in "improper" ways. Daimons appear as anything they please, from humanoid figures to totally abstracted geometric shapes though most have a singular "true" shape which immediately distinguishes them from all other daimons.
Shamans may refuse their daimon's requests, but only at the cost of alienating the daimon. While daimons do not usually select people opposed to their goals, they are capable of enforcing their will by harrowing the shaman, calling hostile spirits to attack, refusing to help the shaman (by possessing their body while the shaman spirit walks to keep out passing spirits, for example), and otherwise making life difficult. Conversely, they reward and aid those who fulfill their requests, binding more closely with the shaman and developing their powers.
Socially, shamans are highly respected by the Kadiz and Hill People, but are a class apart. They travel the plains freely, from tribe to clan to tribe, without interference, and even a Kadiz shaman will be welcomed by the Hill People and vice versa. It is considered good luck to help one, and terrible luck to enslave one. To ensure that there is no confusion over one's status, shamans are tattooed with three lines on their jaw. Occasionally someone will imitate their marking without true shamanic status, though this is highly blasphemous. Unless a shaman can demonstrate their power when challenged, they will be killed out of hand, though most people err on the side of caution. One promise daimons often make with their hosts is that upon the shaman's death, the next shaman to bind with the daimon will avenge their death.
Shamans and their daimons have defied the urge to build grand organisations, so there are no shamanic cults or groups to join. Daimons do not all coexist peacefully, and shamans may be sent to fight one another over what precisely constitutes "improper" behaviour on the part of the spirit world. As a result, shamans tend to be solitary persons, or at most duos, with a student shaman and master, to avoid impromptu violence due to daimonic disagreement.
Pursuit of shamanic power does not prevent one from being a gnostic, though all regular religions ban their members from shamanism and expel members who become shamans (as peacefully as possible). Despite that, shamanism is not considered improper by the nomads, and most tribes have at least one shaman. A surprisingly large number are exiles from the Orthocracy of Kaddish and Dwer Tor who have integrated into life on the plains.