The Iron of the Eternal March is the war-faith of Gorath. It teaches that empire is a forge and conquest is the hammer-stroke, that the peoples Gorath breaks were formless until the blow fell on them, and that the blow is therefore an act of devotion rather than greed. Its priests march with the legions. They consecrate the standards before an assault and the ground after it, and in the slave provinces they preside over the breaking of new labor, blessing the brand and the lash as the first shaping a conquered people receives. The faith holds the primacy seat at Azantir, sends a chaplain to every legion in the field, and counts the empire's wars as its liturgy. While the March advances, the faith is proven. This is the trouble it is in now, because in the Moon Wilds the March has stopped.
The thing worth understanding about the Iron is where it got its god.
A borrowed hammer
Krondeum is not a Gorathi daemon. He is the pan-dwarf patron of hammered iron and the anvil, kept by the First Brotherhood and by diaspora smiths from a dozen clans, and the rite the dwarves keep for him is a small and exacting thing. A smith carries a finished article to a clan-hall fire, names aloud the hand that will carry it next, and lays it on the anvil. The fire only witnesses. The naming is the prayer, and a thing with no named carrier is not finished. The hammer in that rite is a maker's hammer, and the whole of it is about the work being brought into the world whole and accounted for.
The Gorathi took the hammer and left everything else on the anvil. They render the daemon's name in their own tongue as Krondeus, the Hammerlord, and they preach the hammer-stroke as the stroke of empire: the blow that falls from above, the iron that submits, the shape pressed onto raw metal that could not shape itself. Where a dwarven smith names the hand that will carry his finished blade, a chaplain of the March names the province the blade will take. It is the same daemon and very nearly the opposite faith. The First Brotherhood enforces no orthodoxy and lets each clan keep its own version of the naming, so there was nothing to stop the appropriation and no authority to protest it. The Iron does not think of itself as having borrowed anything. It believes the dwarves simply never understood the god they were given.
The hammer does not ask the iron's leave. It falls, and where it falls a shape is born that the iron could never have found alone. So with peoples. So with Gorath. We are the hand that wields the world's own hammer. — from the catechism of the March, recited at the consecration of a legion
The irony sits at the center of the faith and the faith cannot see it. Gorath's slave provinces are worked by Drasnian dwarves, taken out of Tamadrez and off the Pesalolo coast in their thousands, and the Drasnian are Krondeum's people. The empire enslaves the very folk whose daemon it made its war-patron, and it sets those slaves to the forge under chaplains who pray to a Hammerlord the slaves would not recognize. Master and slave bend to the same daemon across the same anvil and call him two different gods.
The hardliners
The head of the faith is the Hammer-Primate, and the office is held by Ozimar, who has built his primacy on a single conviction: that the conquered keep their own rites, and so long as they do, the conquest is not finished. Ozimar reads the Drasnian naming-prayer as sedition with a liturgy. A slave who carries a finished thing to a hidden fire and names its carrier is a slave asserting that the work is his to give and that there will be a hand to receive it. That is a future, and a future is the one thing the empire cannot let a slave own. So Ozimar would put out the clan-hall fires, forbid the naming under the brand, and have the hammer of the March fall until nothing Drasnian is left to fall on. The legions supply this program its muscle. Its instrument among the slaves is the war-chaplain Brasco, who blesses the lash and brands the columns and keeps a ledger of provinces shaped, and who is the face the enslaved most often see when the faith speaks.
The schism
A chaplain named Serel broke with Ozimar over exactly this, and the break has become a movement the Primate cannot easily crush. Serel's argument is plain and, by the daemon's own nature, hard to answer: the hammer of Krondeum is a maker's hammer, the naming is the heart of the rite, and to forbid the conquered the naming-prayer is not to enforce the faith but to misread its god. Serel refuses to be the state's instrument. He will not bless the lash and he will not snuff a clan-hall fire, and where Brasco brands, Serel has begun quietly recruiting among the Drasnian faithful instead, offering them the faith without the erasure. The dissidents have found their truest convert in Brunna Drennak, an enslaved Drasnian smith-priest who kept Krondeum's rite through years under the brand and now keeps it openly under Serel's protection.
The discomfort for Ozimar is that the schism may be the orthodox party and the Primate the heretic. The dwarves have worked Krondeum's rite for longer than Gorath has existed, and they read the forge as incorporation rather than conquest, the finished thing named and carried on, the carrier always accounted for. By the daemon's own measure that reading is closer to true than the Hammerlord the Iron preaches. Ozimar cannot denounce Serel without conceding the point, and so the schism grows in the space the Primate dare not close. Whether Serel believes the dwarven reading or has simply found the one argument that protects his conscience and his converts at once, he does not say, and the faith is not sure which would frighten it more.
The Iron has spent men on the Wilds as well. One of its chaplains, Olivar, was lost into the Moon Wilds years ago on the campaign that the March could not win, and the faith counts him among its dead without knowing that he is neither dead nor wholly lost. What became of him is told where the Wilds are told, and it is not a thing the Iron would want widely known.