The Unbound Realms of Kevvar

No walls as far as the eye can see, no gate nor fence, only the mists and wind roam free over the open lands of Kevvar, softly touching the sparkling sea of waist-high grass. Flocks of water birds rise from the surface of shallow lakes ringed by reed, their wings carrying them like the mighty Roncor carry the tribes.
There, see, a tree wanders by, strewing its over-ripe fruit into the most fertile soil before moving on. Waves race across the grass carpet as it approaches the shrinking lake, its waters drained by the thirsty rays of the suns.
Thunder shakes the land as a mighty herd of wild beast races by, chased by a many-headed carnivore, a towering beast that is so old that its original form is barely recognizable, all fang, plate, tooth now, its hunger insatiable, its roar pure terror.
Could some sound be louder, more encompassing than the beat of those innumerable hooves? There the horizon has darkened, and split open in blinding light. A storm of fury beyond measure approaches, lashing the land with tidal waves that sweep swathes of it into one of the many snaking rivers.
At the center of the storm, two winged figures are locked in a merciless battle, lightning cracking over their armor that seems to be made of seamless metal and living glass, their wings beating the air as they struggle to stay aloft, trading blows, blood, black as tar yet vividly red whenever lightning flashes, spraying from their many wounds. One shall leave, one shall stay.

Movement and change are the main theme of this realm.
Little is set in stone, most is clay or wisps of smoke.

Wide plains and shallow seas are what most of the world consists of. In rare places, protrusions of rock make for more stable terrain. Rolling hills and ragged terrain are most often found further inland, while most of the flatlands are land mingled with water, ever-changing, or seas of grass. Oceans are shallow, frequently changing their coastline, claiming a piece of land here and drying out there. Even forests wander, the restless trees turning their branches as to catch the most sun. Herds without end roam the land, driven by the great Horned Spirit. So does man.

Three kinds of sentient beings call Kevvar their home, as different as they can get.

The colossal Mandaan are of such size that man is not aware of their being more a force of nature to the diminutive mammals, they dwell deep beneath the ground, most often only an earthquake telling of their passing, or a swathe of land sinking slowly as the ground they burrowed through sets. Having come from far reaches of space, they are magical beings of great power and wisdom, having found a calm oasis in the chaos of stellar warfare, where they can muse about the nature of the universe. They are a non-militant fraction of their race; sometimes, they choose to surface, growing mighty telepathic antennae on their backs, flowering crystals of great intricacy and magical power, which they use to contact great thinkers on other worlds. A select few mentor would-be philosophers and promising minds off-world they surface a lot more often.
They are of one of the elder races, who left their traces all over the known universe - most of their number have perished in conflicts in times long past, save for the Mandaan who sought to evade exactly that - war amongst the Elders. Truly, few foes are more implacable than the Elder races, for when you can shape the cosmos, it is your vision, your set course you want it to take; anyone messing with your vision of creation is bound to draw your ire.
A long war makes for a short summary: most of the Elders, of all the ancient species, fell. Still, the Mandaan hide, steering a few choice threads of destiny from their recluse, for who knows whether some of their ancient foes still live, equally hidden, on the lookout for any trace of his ancestral enemy?

In form, they are somewhat serpentine, with a sense array along their backs, and crystalline structures on their heads; they use those to see and hear, or rather perceive. Their bodies are covered with scales of metal they devour as they dig through the earth. Miniature thermonuclear furnaces in their bellies sustain them for extended periods of time; secondarily, they can also function as thaumivores.

Tall and proud are the Samman, sinewy humanoids with mighty manes. Ordinary Samman reach a height of six to seven feet, and, being very conscious of their appearance, are often well muscled. They are digitigrades, with strong claws on their legs that allow for stable footing. Males have a pair of sturdy horns on their heads, with the size corresponding with the ego of their owner, while both males and females grow sharp protrusions along their forearms, thus never being unarmed. Priests and healers file these off, as to make their commitment to non-violence obvious.
Males sprout a meaty tail used to keep balance while running, as well as to bear tattoos; while females sprout two: one, long and sleek with a tuft of strong hair at the end will be a hanger for jewelry of sorts, and is considered very erotic by most males and a few females; the shorter lower tail bends forward to cover the females genitals.
Their dentice and strong jaws protruding into a short muzzle point to an omnivorous diet, though the Samman will prefer a hearty piece of meat over a cake any day.
Northerners grow a coat of glossy fur, much to the amusement of their southern brethren, who will find the northern winter to be a little too harsh for them though.
The Samman possess a very keen sense of vision, and a spot on their chests is quite sensitive to magical auras (perceptivity differs widely some can but tell whether an item is enchanted if they press it against their chest, a select few can perceive whether a stranger on the horizon is a wizard or not).

The Samman walk the world above, oblivious to the nature of the sages that dwell in the bowels of their world. Nomadic in nature, they have erected but one city, Nar-Shadda, a fort on rocky ground, where the numerous tribes settle their disputes before the Council of the Exalted, or in the Ring of Equals. The fort-city also houses the Keepers sages who keep track of history and important family lines. Also within, the temple to Va-Mannho (or Mannho for short), the Creator, is the greatest place of worship on all of Kevvar.
Generally, a tribe is organizes around the herds, which they follow as they wander the plains, further divided into extensive families. The heads of the tribes are the Exalted. Even without their gifts, they were exceptional amongst their people. After feeding upon the sacred Stone Flower, strange power erupts within them, manifesting as exceptional and supernatural abilities and changes in appearance, of which no two are the same often the changes and gifts mirror the character and desires of the Exalted one. If he does not feed on a piece of Stone Flower regularly, the abilities and changes will fade with time; if his supply is sufficient, the Exalted will grow in power, requiring increasing supply of the strange crystal just to maintain his form. What none know is that the strange crystalline structure so simply called Stone Flower is the part of a larger being the Mandaan grow these crystalline structures on their backs, to communicate with other great minds between the stars they are telepathic antennae. Their inherent magic is what fuels the powers of the Exalted, and is used up as they utilize their newfound talents. Once a Mandi finishes his conversation, the used flowery organ, about three yards in diameter, is cast off, a great and hotly contested prize. A different situation arises when a Stone Flower is discovered while still attached. While its energy is far greater if harvested in this state, its owner will strongly object to one of his organs being torn off by some critter. A Mandi will lash out with his powerful mind, as well as shaking the ground violently with the coils of his mighty body; it takes luck and skill to survive this.
Most lucky finders will deliver the Stone Flower to their Exalted, and are rewarded. Yet, some self-confident individuals will keep the flower for themselves, for the temptation of power is great, and the prospect of becoming clan leader also tempting. To reach that goal, the newly-fledged Exalted has to survive the wrath of his former leader though, as well as the ire of any others fearing competition.
Other than with Stone Flowers, the Mandaan supply the surface dwellers with high-grade metal, for when they shed their scales, they create great lodes of metal that requires relatively little processing.

Wild beasts are more economical in the use of Mandaan energies they absorb with their food, or when they happen upon an undiscovered Stone Flower and devour it: they grow in size, might, and hardiness, though especially predators can sometimes grow into fantastic creatures that can be a threat to many an Exalted. Those critters make favorite targets for the most skilled of hunters.

Fractious, hot-tempered and striving for dominance, both males and females engage in various contests of skill and strength, as to determine their social standing. The various tribes and clans compete for resources, and the best hunting and grazing grounds. Generally, hardly any day in the day of a Samman is boring.

The Exalted also struggle amongst themselves, a confrontation of great interest for the masses, and one of great relevance should a tribe lose its leader, it is most likely to be pushed from the most fertile places, and thus suffer greatly.

Metal serves as currency, and most property is in private ownership (though one cannot own, only occupy, land). An Exalted will invariably amass a decent fortune, though he is supposed to care for pregnant females and youngsters, as well as those crippled while serving him, who do not have anyone to support them, and often elderly persons without relatives, this being less of an issue, as the Samman generally tend to stay healthy up to venerable age, and often wander off to die when they feel feeble.

The planet Kevvar orbits a duo of stars, an orange star slightly smaller than our sun, and a red dwarf. Three moons and a strongly tilted axis make for varied weather and pronounced seasons.
The star system, registered as Alexandria in Terran scout logs, also features one hot rockball, one cool terrestrial planet with extensive polar caps and dense arboreal vegetation, one gas giant and a cool rockball on its fringe. Without notable mineral wealth or a strategic location, it has remained uncolonized and the Mandaan might have influenced the minds of scouts exploring it to classify them as uninteresting.
With no wormholes or major worlds in the proximity, it is an ideal place for the Mandaan to hide, and for a band of PC to crash-land, or to come seeking the Voices that they have received over their brand-new prototype communicator, or come seeking wisdom of the Ancients.
The Samman will see newcomers most likely as challenges and their equipment as valuable loot, and while they lack modern weaponry, they are more than a challenge for non-military PCs, and the Exalted are a wholly different matter of course, some of them able to punch a hole into a frontline battle tank.
Tact and stealth may be the way to go.
And of course, whether the Mandaan will be glad to be bothered is a wholly different matter. Some of them may be willing to offer aid in exchange for a discreet off-world service, though these tend to be on the difficult end.