Usaltan's are the colloquial term for a League of spacefaring species that abandoned their modern lives to live a more humble existence in some form of religious pilgrimage.
"We, the one true people loyal to Ordos, came to this system, Leafiaros, to escape from the chaos and corruption of modernity, preferring a more simple and isolated life to better attune ourselves to his will. Our forefathers gathered those who were most loyal, arrived, and shed ourselves of all contact to the galaxy at large; F.T.L. engines, long range communications, anything of the sort. They left without so much as a word and bravely never looked back. We have since then cultivated and grown our people like our great fathers and families of old, spread our beliefs, and all without disturbing the soil or tainting the sky, as to not follow in the same destructive attitudes that led to the very modernity we fled from."
The 'Squires' serve both as basic infantry and worker/construction units.
Squires in General: Clad in basic combat armor, given an SMG, Sword, and supplies, they are the primary workforce of the Usaltan people. Every adult Usaltan is expected to carry a firearm or otherwise be equipped to defend themselves or their religion. While far more advanced than the Flare or Leafis, they aren't nearly as ferocious in combat, and do not use every asset available to them as per a religious doctrine of theirs.
Issarian Squire: Clad in attire fit for their desert hills, the Issarian squires are as spiritually devout as Usaltan's can be, and are extremely zealous fighters. Issarian's are expected to carry supplies and water for desert survival, and are more hardy than their brethren.
Holy League Squire; Given relics of the gods as weapons, even if the most basic of them, the H.L. Squires are the most well equipped for combat, though they rarely are seen actually making combat.
Heretic Squire: Crazed and deadly, the Heretics of the Order of Ascendants take a far more radical approach. They are former squires of all cities driven mad by the warping properties of the things they work with. They care not for honor or codes, only survival, and will fight tooth and nail over even the smallest matters. They use normally forbidden Depleted Uranium ammo in their guns for added danger. The Heretics are rarely seen actually using squires for construction or maintenance or anything however, and are known to be fairly nomadic in nature.
Blackhall Squire: Being Excommunicated for dealing with heathens and hording knowledge, the Blackhalls are an odd one out of the Usaltan people. Their squires wield UC48's, stronger assault rifles compared to the SMG of the others. They carry no sword however.
Catrophin Toiler; Perfectly legal laborers who were caught trespassing Catrophic highlands, Toilers replace the Squire in the Catrophic workforce. They are equipped with explosives to prevent them from getting any ideas of 'freedom' or 'liberty'. The Catrophic people do not align with the other Usaltans, believing that isolation, not mingling with the natives, will achieve their religious goals, so care little for the other Usaltans and their rules. Toilers are melee-only units, but work faster in construction and are good at damaging structures as well.
The Order of Ascendants, called Usaltans by the people of Leafiaros, are my take on the Crimson Cult, with the Heretics baring the most obvious comparisons. Though the OoA are a more well known and organized religion than the crazed thaumcraft cultists, but share the same territorial nature when regarding natives. Based also on Catholicism and organized religion in general, they have decided to procelytize to the native peoples of Leafiaros to bring them to with will of Ordos or whatever.