1. They were introduced into Prax during recorded historical time;
2. They have few, if any, Associated Cults in the region;
3. They have survived after the foreigners departed because they fill some need of the peoples of the region.
Humakt was the first of the invaders. He came into Prax at the head of an army of mixed humanoids out of Dragon Pass possibly as early as 35 S.T., in the Dawn Age.
Pavis was a mortal human, admittedly of special parentage, who came to Prax to found his city around the year 800 in the Second Age.
The Yelmalio cult was imported intentionally by the rulers of Pavis in the year 875 S.T. to help against the barbarian raiders.
The Cult of the Seven Mothers was introduced into the area in 1610 S.T. when the Lunar Empire, flush from its victory in Dragon Pass, invaded Prax to find a route to the sea.
Worshippers of all of these might be found among any nomad clan. Every tribe could certainly muster enough worshippers to support one priest. Often the priest may also rule a clan, and so certain families among the tribes are sometimes associated with certain cults. This varies widely.