The War-Heretics of the Macragge
The Macragge are a curious case - a heretical people who make no attempt to hide themselves - but they are rarely the target of persecution and never the target of holy war. A brief examination reveals why: the Macragge hold that it is their sacred duty to make weapons for the end of days.
They believe that their intelligence is a divine gift of their god, which they name the Macragge, and that it was given so that they may worship through their holy artifice: the creation of engines of war and unimaginable weapons that they consecrate and hoard in vast armories. They hold that, at the end of days, which they call the Macragge, their god will come to them with its innumerable legions, and they will open their armories and equip the hosts of heaven for the apocalypse.
The Macragge themselves are not a warlike people - they tend to keep to their fortress-cities. After all, they believe that their arsenal is consecrated for divine use. However, when attacked or on the rare occasions they work as mercenaries (in exchange for some rare weapons technology or incomprehensible sums they use to fund their sacred work), they promise utter destruction - annihilation and atrocity both swift and terrible, though they refuse to spend their sacred armaments on opponents who have surrendered.
The holiest relics of the war-artificers are the dread All-Weapons of the Macragge - masterwork projects capable of incomparable destruction. While many of these relics are secret, some are known, at least by name: the Geddon Engines, the Dreadnaught Colossi, the Four-Pointed Spheres, the One-Spoke Wheel, the Firmament Ablaze, the Tidefather, and the Immutable Vessel. None, however, are more sacred than the theoretical Pandorican, a mystery which tantalizes the artificer-priests of the Macragge. Potential means for its construction are traditionally contemplated and studied as the final project for a novice of the Macragge priesthood to advance to full priesthood, as well as by aged artificer-priests who have retired from their daily duties.
Personally, the Macragge tend to be polite but aloof. They are a highly insular people, typically only accepting outsiders who possess the spark of genius in the art of weaponcraft. They are lead by their Artificer-Priests and their Tacticians (who develop and study war as worship, and are sometimes contracted as tactical consultants). They place great emphasis on the nuclear family and strong interfamilial bonds, with priests typically being supported by their parents and the families of their siblings (though Artificer-Priests sometimes marry, it is rare for them to have children). The Macragge generallly care little for the lives of outsiders, for good or for ill.
The defense of their fortress-cities is overseen by the city's Masters of the Wall and the City Guard, clad in emerald-green thaumomechanical armor. When working as mercenaries or marching to war, the Macragge don a black-trimmed armor that features even more potent defensive technologies. Macragge mercenaries absolutely refuse to fight other Macragge - if two opposing forces field Macragge, they smaller force will abandon the field, and the larger force will reduce their presence by an amount equal to that of the smaller one.