The dominant cult in the Grazelands is Ernalda, with some 9250 initiates out of a total adult population of around 26,000. The Ernalda cult dominates the Grazelands like no place outside of Esrolia. The Feathered Horse Queen is the high priestess of the cult, and also recognized as the high priestess of Kero Fin for Dragon Pass. She is closely associated with the Maran Gor and Babeester Gor cults (with another 1575 initiates in the Grazelands between both cults). Even more impressively, Feathered Horse Queen is the focus of loyalty of the Humakt cult of the Grazelands, with another 1325 initiates. Together these cults serve as bodyguards, enforcers, and dangerous reminders of the power of the Feathered Horse Queen.
Two husband-gods compete for Ernalda’s affections in the Grazelands. The first is the Yelm cult of the Pony Breeders with some 5000 initiates. Primary Yelm the Rider, they also include Sun Lords, Priests. and the Golden Bow shamans. They are Pure Horse People and refuse to ride or herd any animal except the noble horse. They wander with their horse herds across the Grazelands, living in temporary tent villages that move with them.
The other husband-god is Orlanth Thunderous, with 4500 initiates, primarily farmers of the Barntar subcult. They are closely associated with the other Lightbringer cults of the trade towns, another 2000 initiates, and also have ties to their brethren elsewhere in Dragon Pass.
There are numerous smaller cults, such as the Lowfires, Oslira, Pelora, Asrelia, Ty Kora Tek, Yelmalio, various spirit cults, etc. that total another 1725 or so people.
Finally, there are some 1325 Seven Mothers cultists, mainly around North Post and Maregraze Valley.
This might be even a better representation of the Grazelands:
You can see from those numbers the basic contours of the three groups of Grazelanders, held together by the Feathered Horse Queen. Roughly 18,000 are Pure Horse People and another 18,000 are farmers. About 4000 people live in the three trading towns. Tensions between these groups get resolved by the Feathered Horse Queen.
Think of it like ranchers and farmers in the American West. The ranchers (the Pure Horse People) claimed all the land is theirs for grazing and the farmers defended their settlements and crops. No doubt there were range wars and although the Pure Horse People had the upper hand, demographics (and the Orlanth cult) would have destroyed them on the long run.
Instead, the Feathered Horse Queen crushed the Pure Horse People ranchers and enforced a compromise both groups could deal with. The farmers trade fodder and food to the Pure Horse People and in exchange the herds are kept away from their farmlands in the valleys.
The Pure Horse People view the farmers as tenant peasants, the Orlanthi view themselves as free farmers who coexist with the Pure Horse People.
The Feathered Horse Queen as taken three husbands so far. Two were Sartarite Orlanth cultists, one was a Tarshite. None was a Pony Breeder. She is indisputably in charge. The first FHQ thoroughly crushed the Yelmite leadership in a duel of thaumaturgy. She has the loyal support of the Humakt cult, and all of the Feathered Horse Queens have had kinship alliances with the Sartar Dynasty (at least until 1602 – after that the dynasty was out of power and the alliance was reforged in 1628).
None of the Yelmite leaders have ever been able to compete with the likes of a Sartar, Tarkalor, Moirades, or Argrath. The Feathered Horse Queen takes the husband who succeeds in the Marriage Contest.
Most Feathered Horse Queen stick to speaking on behalf for those who work the earth, tend the horses, for the towns and merchants, and on things of magical interest. But her say is final.
The Feathered Horse Queen heroquested to discover that the Earth Goddess of Dragon Pass was Ernalda (not Dendara) – and then establishing herself as paramount high priestess was one of the great Third Age heroquests.
There was a lot of Earth Religion stuff going on at that time, with the High Queen in Esrolia, the Feathered Horse Queen, and Hon-eel, all reasserting the power of Earth in their own way.
The Grazelanders have three small market cities, established by the Feathered Horse Queen and Sartar. The inhabitants provide worked goods, markets for trade, and other services, and no doubt make a customary payment to the Feathered Horse Queen. The population are almost entirely worshipers of the Lightbringers, Ernalda, Humakt, the Lowfires, or the Seven Mothers – the Yelm cultists would have to give up their lifestyle to live there and so don’t.
Note that Yelm the Rider is normally called Yelm the Archer In Dara Happa.