I'm a bit of a genetics/pre-history nerd, so I thought I'd post this here. I don't know that it's useful, but I think it would be nice to inform the world building in subtle ways perhaps if taken as a behind-the-scenes guide.
Founding Cultures
These are the original proto-cultures, from which all current cultures descend.
Origins of the Hillfolk
This is the most boring suggestion I have, so I'd suggest it first. My suggestion is the Hillfolk are the remnants of the original hunter-gatherer inhabitants of the Kingdom. They were originally much more widespread and diverse, with a spectrum of features and languages and lifestyles that extended into the Charalin plain. Fishing in creeks and streams and lakes was a mainstay of their diet until the introduction of crops and domesticated goats and sheep. In the hills they lived a relatively sedentary lifestyle centered around major sources of fish. In less hilly environments, they would rely more on hunting game and eating wild cereals, but these lowland hunter-gatherers have not persisted to present day Urth. Example cultures would be the Mesolithic cultures of Europe. and the indigenous cultures of the Pacific Northwest.
Origins of the Farin
The Farin are descended from highland hunter-gatherers to the extreme south of Lithmore, who domesticated the three sisters crops (maize, squash and beans), and developed a lifestyle centred around agriculture specialized to arid climates at high elevations. While they were able to displace and merge with the Hillfolk originally from Farin, there crops were not adaptable to wetter climates in the hills and valleys to the North. Indigenous Puebloans would be a real-life example culture. Presumably there are are pockets of Farin-related cultures across the southwest of the continent, but that knowledge of far off lands is not something folks in the Kingdom possess.
Origins of the Daravi
The Daravi originate in the desert river valleys to the extreme southeast of Lithmore, and their ancestors were responsible for domesticating cereals. Their grain-based agriculture spread as far north as the Duchy of Lithmore, and they founded the first lowland sedentary societies there. Patriarchal and hierarchal, the Neolithic societies of Europe and West Asia would be the real life analogues. They also brought cattle and goats to Lithmore for the first time, and the invention of the wheel.
Origins of the Charalin
They descend also from lowland hunter-gatherers, specifically those on the eastern fringes of the Kingdom. Living in more lowland areas, they hunted large game and eventually domesticated the horse. This domestication of the horse allowed their ancestors to expand rapidly into suitable environments across the borders of the present-day Kingdom, before gradually mixing and being pushed back. Because of the freedom allowed by the nomadic lifestyle (and the lack of wagons or wheeled vehicles in general), and the constant threat of raids from other nomadic tribes, women were trained to fight and gained greater status over time. The real-life inspiration would be steppe cultures in general and the Sarmatians in particular, with their greater gender equity.
Origins of the Tubori
The Tubori originated in a archipelago to the extreme west of Lithmore. The first true masters of the sea, they spread along first the coast of the the Dralth, eventually colonizing Vandago and the shores of the Kirulean. They did not originally practice agriculture. Whether due to natural sea level rise or due to tinkering with elemental magic, their home archipelago became submerged, leaving their colonies and seafaring technology as their legacy. Real-life examples would be the Phoenicians, the Indigenous cultures of the Pacific Northwest, and the Austronesians.
Derived Cultures
These peoples are the legacy of mixing of cultures. They do not wholly derive from any one specific group.
Origins of the Vandagans
Vandagans are a mix of indigenous hunter-gatherers and Tubori colonists. As Tubori traders and settlers arrived on the coast, they mixed and traded with the indigenous cultures, blending the two together. The resulting mix was neither one nor the other, but with Tubori influence stronger in the south and west coast, and hunter-gatherer influence stronger in the north and east, where reindeer herding is more prevalent. A small layer of proto-Daravi agricultural influence also persists in the language and culture of Vandago. Kievan Rus' blended culture seems like a reasonable analogue.
Origins of the Lithmorrans
Lithmore is a true melding of cultures. The first inhabitants of this land were the lowland cousins of the Hillfolk; however, they were soon joined by the far more numerous proto-Daravi farmers from the south. These farmer-settlers gradually expanded their influence throughout the lowlands, while trading with their Hillish neighbours who persisted in the highlands. Tubori traders eventually made their way up the Bren in search of timber and other raw materials, as Lithmore City is the deepest navigable point into the continent's interior by river.
This society based on trade and agriculture grew prosperous over many centuries, but eventually attracted the attention from proto-Charalin raiders from the east. These Charalin raiders conquered the more sedentary society, bringing with them their herds and their dairying culture. Over centuries, these proto-Charalin elites settled down and merged with the sedentary society, forgetting their history and origins. They however left a legacy of relatively equal treatment of women, as well as the fair colouration that has become dominant in the region.
The expansion of nomads into settled lands has many examples in history. An example of that can be seen in Rome, where the language and culture have roots in the Indo-European expansion from the steppe, but with the Romans retaining no memory of their previous days as nomads. Romans themselves were then conquered by more mobile peoples like Germans, and in places like the Great Hungarian Plane these late antiquity "barbarians' were themselves conquered by other intruders from the steppe like the Magyars. I think a major difference here though is that while the Eurasian steppe is huge, I think the Charalin plains must give way to desert at some point, and are not capable of supporting the massive numbers of invaders that saw groups like the Huns and Mongols wash over an entire continent.
Origins of the Vavardi
The Vavardi are the youngest of Lithmore's ethnicities. They trace their origins to Tubori trading colonies and their relations with Charalin to the east. Over time, this mixing of peoples gave the Vavardi their more Charalo-Lithmorran physical features, rather than their originally darker features. These features were only reinforced by the waves of merchant elites that came during the Consolidation. The language itself maintains many Tubori features, though Lithmorran terms are becoming increasingly common.
Real life inspiration would be the trading colonies of the Italian and Greek city-states, particularly those in places like Crimea.
Situation Today
This region of Urth is cosmopolitan, multiethnic, and mixed, with no group entirely pure. However, a growing population in the agriculture regions of Lithmore and Vavard are putting pressure on local Hillish and Charalin groups, generating conflict in areas where the Kingdom's control is weaker. This tension between migrating peasant farmers and local societies, combined with the "civilized" societies' senses of entitlement and superiority, create political challenges for the Kingdom going forward.
Notes on Magic
My thought on Lithmore's magical traditions is that the hunter-gatherer groups across the continent (including proto-Farins, proto-Daravi, proto-Charalin and proto-Hillish) practiced various forms of animism and spiritualism, communing with magical forces of various natures. It would be among the proto-Daravi's settled cultures that "modern" magic began to take shape, but it was not until the addition of more elemental-focused magic by the Tubori that it reached its pre-Consolidation form.
The Daravi culture influence over magic is what ultimately brought it's downfall, as its hierarchy and structure created resentment of the elites.
