Byssia contains one major culture of humans, half-elves, and wood elves, called Night's Children. They are religiously unified in their diversity of thought.
The Night’s Children, both humans and elves, are unique in that worship of the Congregation is looked down on and unusual. They accept that the Congregation exists and has power. But to them, they’re nothing more than the middle-management of the universe. A 21st-century Earth person wouldn’t pray to his boss’s boss, or to the local Assistant Subdirector of Waste Management at the county offices; no more would a Byssian pray to the gods.
Much more important are their own ancestors and the local kami. A syncretic religion involving those two has taken root. “Above and Around” is a term used—ancestors watching over mankind from Above while kami are involved Around us. While wood elves naturally feel more associated with those Around and humans with those Above, both venerate and propitiate both realms.
Worship happens both at home (where homes have shrines built to honor chosen kami and ancestors and prayer and ritual offerings are made daily) and at local shrines, where Odigos (Speakers for the Unseen) mediate between the ancestors, the kami, and the people. They are supported by the ritual offerings of food or coin; in return they intercede with spirits. Most of them are druidic practitioners, but their circles teach an interface with all spirits, rather than just those of the natural world. Wandering monastics handle the larger matters (when a kami is angered or unsettled or an ancestral grave is desecrated).
Shrines large and small (some merely a rope tied around a tree, others like miniature cities) dot the landscape. Truly Byssia is a Godless land that is full of gods.