"The sun cult" is a popular one

A cult of desperate Sheol sympathizers who aim to appease the Red Horde's onslaught by offering up the lands and lives of those who work to fend off the denizens of Sheol.

In 2261, the Red Sun was merely an infant cult of scared religious types who wanted to barter and talk their way out of the Red Horde's jaws, never to realize the futility of such endeavors.

To make it worse, the Red Sun has evolved into sects and cells who seek power through Sheol, and many have raided Xen'toma Cells and ruins to rob them of their Arkuratalan'tai to use as instruments in their "war".

It is thoroughly believed and preached by the Speakers of the Red Sun that Sheol will inevitably consume the world's unfaithful populations and empower its believers.

As they are seen as a dangerous entity to society, they must often hide their places of worship in slums or outside the boundaries of cities entirely.

You must bring forth at least one recruit per month, or be tossed aside in favor of more a resourceful follower. Take action or take your leave.

The Shattered Sun believe that a world reigned by whoever the Red Horde's leader is will be a world of ease and bliss, to summarize it.

Seeking out Lords, Seers and stray Hellions

Initiates must donate a quart of blood to a pool meant to show their resolve for the Red Sun's ideals and feed any Lords they may bring in as idols.