Storm Tribe: The Cults of Sartar (2001)

From the publisher:

This is the companion volume to Thunder Rebels. It describes the minority cults and societies that are important to the Heortling culture and Orlanthi religion.

It highlights Humakt, Urox, Elmal, Issaries, other Lightbringers and many others; as well as the Orlanthi shamanic traditions. It includes long write ups for a few deities, and short forms for the rest to give affinities and sample feats. Myths about these gods and goddesses are also here, as well as articles on miscellaneous Orlanthi information such as arm wrestling, kite flying and where the Lunar regiments are headquartered and patrol. Finally, it has information on the other "not quite right" people that are in the world, like Ducks, Telmori, and the trollish tribes of Kitori and Torkani.
Scheduled for December.