Death in Holmcrag
Officially, the only legal religion in the Empire is the Imperial Cult – worship of Her August Personage, the Eternal Empress Draped in Scarlet as the sole and infallible representative of the Divine on the mortal plane. In practice, Kipukivi has always been riddled with mystery cults & the Elnar never entirely gave up the trappings of their ancestral beliefs.
The people of the heartlands have always prayed to thousands of petty gods (like Behzd, God of Lost Items & Zikcub, God of Sickly Animals). When the Empire took possession of the region the Eternal Empress became just one more god to honor.
The Bardur Kingdoms
Many Bardur, converted at the point of a sword, never committed to the Imperial religion on a greater than superficial level. Others wholeheartedly embraced the worship of the elves as an alternative to the obscene serpent religion that held sway there before. While commoners typically practice the Imperial religion, there are both Black Clerics & laity among the prouder Bardur nobles.
The Vren Peninsula
The Vren practice a form of ancestor veneration predicated on the notion that the dead continue to exist until they are forgotten by the living. Dying without having performed some great deed to be remembered by is tantamount to never having existed in the first place. Vren villages usually have a shaman who is responsible for being able to recite the lineages and deeds of the ancestors of their village.
The Fell Mountains
While the Iron Dwarves acknowledge the existence of a handful of gods, they don’t worship them so much as hope to avoid their notice. The dwarven pantheon are cast as advanced beings from whose sciences sorcery was derived and to whom the peoples of the known world are as ants. Those dwarven priests that exist tend exclusively to perform rites oriented around propitiating their dire pantheon and keeping their attention focused elsewhere.