This is a big tent, with some 700,000 followers. One way of thinking about the Stygian heresy is that it is tantric Malkionism. Transgressive, antinomian, esoteric, with secret initiation rites and interaction with raw elemental forces.
Gods, spirits, and elemental archetypes are worshiped as revelations from the Invisible God. The destructive storm gods are invoked, forces such as Darkness, Death, Disorder, and Illusion embraced. Weird variants of well-recognized deities are worshiped symbolically (but sometimes worship take the symbolism literally), and more. Half-understand glimpses of Arkat’s heroquests are worshiped as secret insights into the nature of the cosmos.
There’s no real organization to the Stygian heresy, and no agreed-upon set of doctrines except that understanding Arkat’s heroquests are key to understanding the cosmos.
From here we can imagine the Chariot of Lightning movement in Otkorion to be like Krishnaism, and they center their devotion on Orlanth as the Creator God, and the avatar of the Invisible God who restored the cosmos.
The idea that Surentyr the Nonheretic has pilgrims dancing around Tinaros, Kustria, and Sentanos while singing mantras about Orlanth, the Invisible God, and the Lightbringers, like they were from the International Society for Krishna Consciousness, amuses me greatly.
And it would absolutely gob-stop Orlanthi from Dragon Pass.
But it would help explain the rapid spread of the movement, particularly among the Stygian heresy.
It should also be observed that there is somewhere around 1.5 MILLION Orlanthi in Ralios.