I would also be against a Discord - I've seen a lot of RPs sputter and die out as soon as one is introduced, simply because everyone is talking too much about the things that their characters might do or the places the story might go and nobody's actually posting, as well as the fact that the discussion can move so fast that less active people tend to be left behind and drift away from the RP. Just my two cents, though.

If Barsabbas spent any time in the Godsfangs at all, he probably had some interaction with the strong people that make that land their home.

Barsabbas, the "Phantom General" [+]

Barsabbas wears armor and wields weapons of Soulsteel, crafted in the pits of the Claws by unknown means.

Barsabbas Ahsaz

Description:
Barsabbas commands the Firebrands, a rogue warband that operates from the north of the Red Desert. Once, Barsabbas was an esteemed Salished cavalry officer; now he operates independently under no jurisdiction but his own. Attempts by the Shashul to bring him to heel have met in failure, as his warband eludes capture between the Claws' twisted maze of rock. This notoriety has earned him the moniker of the “Phantom General.”

The theories as to why Barsabbas broke away from the Empire are many, but only he and a number of close confidants know the truth. Three years ago, Barsabbas journeyed into the Godsfang Mountains, the lands of the Saliszis' ancestors. He claimed to be led by visions of the Forge Gods, and took an entourage of six of his most trusted advisers with him on the journey. For months they disappeared from the public eye, until it was reported that a number of Barsabbas's ranks had deserted their posts, taking with them valuable Soulsteel ingots and weapons, and several of the smaller, mobile counterparts to the great Soul Forges.

Whether Barsabbas and his men communed with their hungry Forge Gods at the peak of the Godsfangs, or learned some awful truth from the Crone Wisdoms, or made a pact with another entity entirely, no one can be sure. All that can be said with some certainty is Barsabbas has the means to produce his own Soulsteel, without the fires of the true Soul Forges, and has the support of several desert tribes: Avanagashans and Varyonese.

Race: Human: Saliszi
Faction/Unit: The Firebrands
Location: The Claws

The Firebrands [+]

Massed tribal cavalry makes up the core of the Firebrands' fighting force.

The Firebrands

Type: Warband
Faction/Unit: Loyal to Barsabbas
Description:
The Firebrands, as they have come to be called, were elements of the Salished war machine under Barsabbas's command. Many followed their commander as he went rogue, either out of personal loyalty or an intent to see his plans realized. They operate from the shadow of the Claws, having carved their domain out of the narrow passes and treacherous crags. This provides them with a natural defense and hiding place with which to undertake their machinations in secrecy.

Deep inside the Claws, one can sometimes see towers of smoke churning from the makeshift forges Barsabbas uses to craft his own Soulsteel. How he's managed to replicate the process without the holy Soul Forges is beyond the Salished's comprehension, but the weapons made in this manner are not a one-to-one match with those that emerge from the fires of the true forges. These are no less effective, but glow with baleful energies and are known to shriek as they kill. Attempts to follow the trail of the smoke to the Firebrands' whereabouts is a treacherous prospect, as booby traps and hidden fortifications are strewn throughout the passes.

From the Claws, Barsabbas stages raids on weaker factions to gain valuable supplies and offers the defeated a place under his banner. With every victory his losses are replenished with new bodies, yet he keeps his ranks compact enough to conceal and maneuver without great difficulty. Though the Firebrands retains a sizable core of cataphract cavalry, most of its numbers are light horsemen and skirmishers drawn from local tribes. Befitting of their leader's nickname, they appear suddenly, harrying their enemies from unexpected directions before picking off disorganized elements piecemeal. Then, they will steal away whatever assets and valuables they can find before vanishing as quickly as they arrived.

Heavily-armored cataphracts act as Barsabbas's elite soldiers.

Since the Saliszi came from a single tribe of mountain folk, the Arakkai living there now predate the Saliszi empire.

Edit: @Aristo Perhaps the original Saliszi were exiled for their practice of human sacrifice by the other tribes of the Godsfang mountains.

<Snipped quote by Nieszka>

That's fine; I guess there could be numerous tribes of people that have called the Godsfangs their home.
Though it might be a stretch for the Saliszi to have been kicked out - as written in the OP history, they already had Soulsteel by the time they conquered the Rainland, which likely means they were the dominant power in the Godsfangs beforehand. That's open to interpretation, of course.

I'd imagine the Arakkai have lived under the shadow of the Salished since its founding, and either are too elusive or aren't worth the Empire's time to try and conquer.

I can certainly work with that, though I don't know how to work good Salizsi into my tribal lore. What say you to the origin of Soulsteel? @Flagg

That idea is a cool one to me. How would the bargain affect everyday users of soulsteel? Is there a price for using the superior weapons?

<Snipped quote by Nieszka>

Use would progressively open users to possession. The cult has elite fanatics who are basically controlled by their weapons. Saliszi nobles only wear their weapons in battle to avoid such a fate. Only extremely strong willed or otherwise protected individuals could resist the demonic influence over time.