Obviously, much of the following information would not be known to a character living in the world.
The continent lies chiefly in the northern hemisphere though it bridges the equator. From northern tundra to southern tip it is some 13,000km while from west coast to east coast it is some 6,000km (on average).
The entire population of the continent is under 15 million with most of these being human though several hundred thousand are other intelligent species. The chief population centres are north-east coast (Atari Isev), south-east coast and inland (Lujnashra), mid-north plains (Kaer), northern steppes (Nadda), southern deserts (Dragonnewt) and south-west coast (Yauj).
Atari Isev daily life is governed by clan economics and politics. Approximately two-fifths of the nation's populace belong to one of the 311 recognised clans which typically are groups of inter-related bloodlines that control a craft or trade. The other three-fifths of the population tend to be rural farmers or the dispossessed (clanless). Both intra and inter-clan politics are particularly ruthless and machiavellian.
Atari Isev was formed somewhat over 300-years ago when a mass exodus of people fleeing a cultural disaster landed on the west coast of the continent. In an epic struggle these refugees crossed the Kaer plains to found the new nation on the east coast.
A great cultural hero named Sendath led the way and laid the foundations for many of the institutions of the new nation. Treaties with the Kaer tribes were formed and a government system based on a ring of seven equals was formed. These institutions survive today as well as the major cities that Sendath planned and built.
Atari Isev's considerable power stems from the rich resources of its land and its advanced technologies (farming, economics, warfare). The northern regions of Atari Isev are rich in a number of ores while the south is the "grain belt" of the nation. Atari Isev has a well organised and disciplined army that includes a small cadre of battlefield magicians.
In the last 100 years Atari Isev has stagnated somewhat and its influence and control over distant nations has slipped. Today the average citizen's thoughts are turned inwards to clan politics and personal advancement.
Kaer culture is hunter-gatherer based with a yearly cycle of movement that brings the tribes together for the summer rituals and sees them break up into small groups of 10-40 families to see out the winter.
The Kaer have a deep spiritual relationship with the land and recognise and interact (usually through their shaman) with many spirits. During their rite-of-passage most Kaer are visited by a spirit (e.g., Eagle or Bear) who gifts them with a minor power.
Individually the Kaer have much personal responsibility for their own and their tribe's welfare. An individual's action determine the respect they receive and whether their voice is listened to at councils. Leaders are only followed while they display the virtues that make a great leader and each follower has personal choice.
The arrival of the peoples of Atari Isev has greatly changed the Kaer culture with the introduction of the horse, metal implements and weapons, and even the adoption of agriculture by one tribe.
The Kaer have two great culture heroes who are reborn every 100-years or so. They both bring change to the Kaer way of life:- Sa-Kun-Ta is a male war leader, while Ho-Ne-She-He brings innovation and new ways.
The Sylthaen are a hybrid animal-plant kingdom species that goes through four distinct physical periods in its life-cycle. The child form is known as a Qwyst and is a fragile darting humanoid creature under 1 metre that appears to have limited individuality or intelligence. The second stage and best known to outsiders is the Sapsu, an androgynous humanoid form. At this stage of their life the Sylthaen are overcome with curiosity and wanderlust and travel the world. The third, mature adult stage is known as a Trahee and is a 2+ metres creature that appears to be part humanoid and part tree. The Trahee are the caretakers of the forest and Sylthaen society. The fourth and final stage is a Krythaen tree in which the individual surrenders its memory and spirit to the overmind that governs the culture.
The final form of the Sylthaen while physically a majestic tree in reality is a group mind consisting of all the Krythaen in the forest. The overmind's power is directly proportional to the number and experiences of the Krythaen within the forest. Typically it has god-like abilities over flora, fauna, weather etc. within the forest. The Trahee are the intermediaries between the overmind and the rest of the Sylthaen.
The Sylthaen are "born" from Krythaen trees as Qwyst and are split into three distinct classes, that determine physical and mental characteristics, based on the location of birth. The three classes correspond to Root, Trunk and Branch. Dependent on this class a Sylthaen often displays unique abilities (e.g., can harden skin like bark). Qwyst born at the same time from the same tree share a special relationship that endures their entire life.
Qwyst re-enter a Krythaen tree to undergo the transformation to the Sapsu stage. At this time they are also granted a special wooden "heart" weapon by the tree such as a bow or spear (exotic weapons such as bokken or boomerangs also occur).
Sylthaen dietary requirements include large amounts of water, direct sunlight and small portions of food (the better de-composed the better). Seasonal and day-night cycles also appear to influence Sylthaen behaviour.
The Duerager's special relationship with earth manifests in both their appearance and personality. Duerager are approximately 1.5 metres in height with broad shoulders and angular, rather than rounded, features. They are particularly hardy and strong, while their skin colour varies significantly dependent on which mineral or metal is their calling.
Each Duerager has an affinity or "calling" for a particular mineral or metal (e.g., iron or granite). The affinity expresses itself as a shift in skin colour towards the mineral or ore, a desire to work with the mineral/ore, a personality that reflects some of the properties of the ore (e.g., firm and hard for granite), and possibly unique abilities related to the mineral/ore.
Duerager society is very structured with every adult being assigned to the role or job they are best suited to. Those who will not undertake the job are ostracised and eventually leave the community. Aptitude is determined for a battery of test with leadership and senior positions being filled based on performance in tests designed for the position.
Duerager are exceptionally skilled in all crafts that concern the element earth including mining, ore extraction, civil engineering, smelting and smithing. They greatly value lasting works. Many Duerager are equipped with the unique ability known as [true] smithcraft by which special abilities can be imparted to metals and gems. Further Duerager are particularly advanced in some areas of chemistry and technology as compared to other cultures.
The major portion of a Duerager settlement is underground with a section being maintained above ground for security and dealings with humans and other species.
The Nadda have strongly separated gender roles with male as herder, hunter and warrior/raider, while female is farmer, child raiser, barterer/trader and housekeeper.
Nadda wealth is measured in the size of the horse herd that is owned. The horses are a unique mountain breed, almost as small as a pony but extremely hardy with amazing endurance. The Nadda are pre-eminent horse-archers and their basic war tactics are skirmishing and harassment.
Martial strength is greatly respected and an occasional war-leader will unite a great army of warriors and lead it swooping down to the lower regions. 100-years ago a great army raided into northern Atari Isev but was eventually smashed. While Atari Isev maintains a constant guard on the region its peoples are too scattered to be able to maintain rulership over.
For 130 years Atari Isev clans exported (plundered?) much of the wealth of the region before popular unrest and uprisings drove most out. Government was handed back over to Lujnashra nationals but using the Atari Isev template. The nation rapidly collapsed into groups of warring factions each vying for ultimate power.
Recently, a great prophet from out of the deep desert regions has been preaching the word of a new god and uniting the tribes of the region.
The peoples of Zambeti are tall and dark of skin and use a slash-and-burn form of farming, with hunting and gathering also meeting about 35% of their dietary needs.
The lack of national government has allowed some of the powerful Atari Isev clans to set up exploitive plantations on the rich Zambeti soil virtually unopposed.
Each Zambeti tribe has a totem animal spirit which is placated and appeased but also grants special powers to the spirit chief and the tribe in general. Some tribes with warlike totems have been active in attempts to throw out the Atari Isev clans.
The east coast and northern nations know little of Yauj except that its peoples are great sailors and corsairs--raiding the coastal towns and cities and plundering their wealth. Only Atari Isev has navies capable of combating the Yauj and now that they have withdrawn from Lujnashra the southern coasts are once again open for plundering.
Atari Isev has a treaties with 5 of the 9 great Kaer tribes allowing free passage. This stems from Sendath's first crossing of the continent. Today Atari Isev maintains border watches along the hills that separate it from Kaer and there are numerous small raids and the rare attack that must be turned back. Despite this considerable trade for furs and finished products occurs between the two nations.
The Duerager settlement exists inside Atari Isev. They are recognised as an independent state and remain particularly insular from the surrounding nation. However brisk trade occurs and the settlement pays a yearly "tax" to the government of Atari Isev.
The Sylthaen forest exists on part of the Kaer plains and for hundreds of years there has been strife between the Sylthaen and the local Kaer tribe. Sendath brokered a treaty which still shakily holds but there is little dealing between the Kaer and Sylthaen. A small Sylthaen forest can be found in the Atari Isev capital Eothnia and there is good relations (such as there can be) between the two.
The Nadda and Atari Isev remain in a state of suspended animosity. Atari Isev would like to see the country severely punished or brought to heel but there is no infrastructure to seize or destroy. As such one of Atari Isev's legions is always maintained on this border.
Trade between Lujnashra and Atari Isev is brisk but threatened at times by the sleek corsairs of the Yauj.
The government of Atari Isev continues to turn a blind-eye to the situation in Zambeti based on the policy that it is not a nation but "...unsettled land..." which "...[the clans] are developing".
The last major acts of warfare have included an Atari Isev army smashing an invasion from Kaer (about 80 years ago) on the border, and an Atari Isev army finally cornering and decimating to a man a Nadda force that had been pillaging northern Atari Isev.
The most sophisticated form is magery as practiced by the sorcerers of Atari Isev. It concerns the manipulation and combination of fundamental magical elements to form spells. The ability is very rare and difficult to train but quite powerful.
While sorcery is the manipulation of fundamental magical elements for spontaneous and short-lived effects, smithcraft is the binding of those same elements into metals and gems to achieve permanent effects. True smithcraft is also a rare gift as well as a difficult path to master. Smithcraft is possessed by the Duerager and some rare humans.
Shamanism and religious powers both achieve effects through the agency of a 3'rd party. In the case of shamanism they use their spirit-guide or spirits with whom the shaman has a pact or can offer an inducement to achieve the desired result. With religious powers the priest or avatar receives intervention from their god. At times the shaman or priest/avatar may be directly granted abilities or powers. This is also true for others who have a limited pact (gift) with a single spirit (such as most adult members of the Kaer).
Finally, certain intelligent species such as the Duerager or Sylthaen possess abilities most easily described as magic due to their very nature and strong affinity for a particular element or aspect of the world.
Most cultures have their own set of gods with their own aspects and spheres of influence. Through the intermediary of their priests these gods influence the world by such mechanisms as enhancing (blessing) crop growth, healing the sick and cursing the blasphemous.
The seeming paradox of different cultures possessing different gods but with similar and overlapping aspects (abilities) resolves as follows: Gods and mighty spirits etc. are cultural projections or anthropomorphism upon certain universal forces or principles. Through worship and belief splinters of these principles/forces acquire an individual existence and personality.
This relationship of belief/projection and universal principles is understood or suspected by very few though it was once a pivotal aspect of the culture from which the Atari Isev immigrants fled. The deliberate, culture-level manipulation of this relationship led to the destruction of the culture.
This world is one of strong spiritual forces and ideas. Strong emotional and spiritual events in the "real world" leave their mark in the spiritual and strong individuals and forces linger on in the spiritual world long after they have vanished from the material one.
The barrier between the two planes can be pierced by those with the ability. Shaman enter the spirit world to contact allies and the fundamental concepts manipulated by sorcerers may find their source here. Similarly strong beings and forces from the spiritual plane may occasional cross the barrier and bygone or mythical creatures once again find their way into the world.
In general iron (steel) and the wheel are in common use in those civilisations that have towns and cities. Gunpowder has not been discovered, but water and wind power are used. Paper exists but there is no printing press, with woodblock printing still being the only means to mass-produce writing.
Crop rotation and irrigation are understood and used as well as animals to draw and carry loads.
Coal is used as a fuel in heating homes and coke is produced for metal-working furnaces. Steam power is not understood except maybe by the Duerager.
Wagons with spoked wheels are used for carrying loads and ship design is similarly advanced. Horses are commonly used for individual transport and the art of animal husbandry and breeding for strengths is well understood.
Medicine is poorly understood with no accurate holistic model of anatomy and physiology. Rather it is a grab-bag of knowledge and experience concerning the best treatments for certain ailments or symptoms.
However it is expected that most of the on-going game will be centred in Atari Isev though with possibly frequent expeditions to other cultures. As such PCs from outside Atari Isev should be designed with this aspect in mind--a deep desert swordsman from Lujnashra isn't going to see much play unless he leaves Lujnashra (this can be engineered during the prelude though so don't let such concerns get in the way of a character concept you like).