Ave! Ave! All Hail The Imperium!

"Why do we struggle? Well, you want to know how it ends... yes?"

Kelmorn of Lotk, Sage

Welcome adventurer, to the world of the Imperium.
The campaign world is vast - a harsh and dangerous landscape that has been under the iron boot of the Imperium for decades.
The Imperium is - for all intents and purposes - a police state, one that controls all the known territories of the continent (or so it is reported) and whose presence cannot be ignored, as its military is ever present wherever one goes. Cohorts of soldiers tromp along every road and highway. There is an Imperium garrison in every city and town, forts and citadels dot the landscape. From the coast of the Everdeep to the foothills of the Ragefang mountains that scrape the roof of the western sky, from the northern tip of the Shattered Wastes to the southern peaks of the Hound's Jaws, the Imperium rules supreme. All the cities and towns that within these expansive territories, including ancient ruins, forgotten holds and abandoned keeps, the S'lka mines and factories, and the enslaved that work them, all this and more falls under the watchful eye of Imperium Tribunes and Centurions.
Though the Imperium has been a major power for close to a thousand years, there are two events that have taken place in the last fifty years that may impact you as a player.
The first is the Last Scourge, also known as the Year of the Cerulean Sun.
Fifty years ago, the Last Scourge saw the end of the human/demi-human wars, the culmination of which saw the Imperium's military power consolidated and creatures known as Orcs, Goblinoids, Elves, Gnomes, Tieflings etc. all but exterminated (or so it has been chronicled).
Dwarves and Halfings are not separate races in this world, but are a variant Human sub-race called Half-Men and are considered normal folk by all Imperium citizens, though they do keep the racial benefits as outlined in the rule books. Most Half-Men are melders and therefore it is very rare for them to be seen out and about in most cities and towns, though there are exceptions.
Before the Last Scourge took place however, a near world-ending cataclysm devastate the whole of the Imperium. A great volcanic eruption far to the west, filled the sky with a blanket of ash which blocked out the sun for close to fifteen months, reducing the amount of light and energy and making appear as though the star were burning blue in color - and so is remembered as the Year of the Cerulean Sun. Crops failed, mass starvation and famine followed. Pestilence and disease stalked the land and close to seventy-five percent of Mythari's species and population was wiped out. Demi-humans were hit the hardest and thus led to them not being able to defend themselves in the final battle.
The second event was the Ascension of the Imperatrix. The head of the Imperium took the throne after the last rebellion was quashed twenty years ago and since that time, Selune Na’Joris has ruled with an iron fist, crushing all who oppose the Imperium and ruthlessly hunting down its enemies.
From a player perspective - any race is still open to play.
However, if you chose a demi-human race, we need to justify how you have survived in an ALL HUMAN campaign. For instance, are you a Dragonborn whose physical appearance has stifled its draconian heritage and is in danger of manifesting at any time? How as a Tiefling can you successfully hide among a population that would burn you at the stake should they discover what you truly are?
If races have twists unlike many other D&D campaigns, so too do classes:
All magic users, be they clerical, sorcerous or wizardly, are strictly controlled and owned by the Imperium. If you want to be a spellcaster above that of 1st level -- you are either going to be a conscript of the Imperium or you are an outlaw that will be hunted by them. There are no magic items* circulating among the general population. Any item that exhibits magical properties or potential is confiscated and catalogued by the military arm of the Imperial Republic, stored in secretive vaults or sent to research camps for military applications. All of these elements can be discussed with the DM in our session 0/character creation gathering.

That isn't to say that magic is absent from the world or beyond the player's reach. It just has to be carefully hidden from the ever watchful eyes of the Imperium. Many magical items do not appear as they are described in the D&D 5e source books - for example, a +2 magic sword could simply be a masterwork S'lka weapon.
What is S'lka? S'lka is the ubiquitous material that is the bedrock of the entire Imperial machine. A crystalline silica-based compound mined from deep within the earth, and once properly processed in factories, S'lka is used for all manners or construction and martial purposes.
It can be used by melders to make blocks of nigh impenetrable stone, marble or other building materials. All walls and structures in the world are mostly made from S'lka. It can be molded, bent and folded to make weapons, with those accomplished smiths and metal workers able to craft items of near magical quality. Mixed in with other metals, gemstones or even glass, results in objects of exquisite beauty. It is not unusual to see glass swords or pieces or armor for example.
Melders are individuals that have a unique genetic trait, one that is viewed by many as either a defect or a blessing - they can, with their bare hands, meld S'lka. Anyone who exhibits this trait as a child is scooped up by the local government and shipped off to Tarnhomme, where they are schooled in the art or craft of melding, to then be assigned to either a weapons or materials factory. Some rare few are taken in by the wealthy elite, to create sculptures, statuary, monuments and other works of art. As mentioned earlier, and with rare exception, all Half-men (Dwarves & Halflings) are able to meld to some degree.
Outside the walls of the cities and towns, the wilds of the continent are hazardous and dangerous. Even with all its might and presence, the land is still plagued by tribes of bandits and outlaws - and the occasional monster. Caravans and S'lka trains are raided frequently. And on rare occasion, some strange and monstrous beast is said to terrorize farming communities and villages.
Before the Imperium's Military mandate concerning those with the affinity, talent or skill with magic, joining a Caster's Guild was paramount if one wanted to earn a living. Casters were well positioned to become movers and shakers in the political arena of cities and towns, or else as advisors and court seers for the several dozen royal houses. Once the Imperitrix demanded all magic users register with the military, the Guilds all but disappeared - as did a great many spellcasters who fled across the Ragefang peaks to the West or sailed for unknown destinations across the Everdeep Sea to the east.
For those whose casting ability was minimum or non-existent, there was coin to be made as swords for hire, known to all as Slayers, though many id not look upon them favorably. They were not just mercenary killers, tasked to undertake all manner of violent and dangerous jobs - but they also stalked the land hunting and capturing fantastic beasts and fearsome monsters for the Delving Games.
Which brings us to the last way restless adventurers could earn fame & fortune by becoming one of those odd individuals who call themselves Delvers.
A delver is a kind of gladiator, a hearty soul who bands together with those of like mind who then risk life and limb by attempting to best the strange mazes and dungeons specifically built to test their skills and abilities. Delvers are also the rare few that can - if they are of the spell casting sort - that can avoid military conscription, by becoming licensed. A delvers license allows one to use ones gifts beyond 1st level without penalty. Though, all items and treasures collected during said delves are property of the state and must be surrendered once the delvers emerge from the depths. They are compensated in coin for whatever they uncover, and also receive the adulation of the people.
There are groups of delvers that have achieved fame and fortune and whose names are known throughout the Imperium. The trick, of course, is to survive long enough to enjoy such things.
So tell me... you do want to know the end of the story, don't you?
* Regarding magic items - as the D&D game relies on magic and magic items for PCs to survive various encounters or to overcome obstacles & traps, etc. the note about there not being any magic items in circulation is not true at all. The Imperium propaganda machine will tell you otherwise however. Certain potions and salves can of course be purchased at shops and alchemist stalls in every major city.

If a magic weapon, staff, ring or what have you be used in public to harm or cause mayhem and chaos, of course the Imperium will pursue any lead to find and secure such dangerous items - and woe be to those who get caught. The Imperium prisons are dark and dank, and the stake and gibbet await all others if the cells are too over-crowded.

The Whole Wide World

The night sky is filled with swaths of constellations and clusters of stars, swirling clouds of space dust, distant moons and planets. It awe-inspiring vistas compliment the strange beauty of the world above which it spins.

Mythari is an old world, very old. It has seen seven ages come and go, it's golden sun continuing to light its days, the twin moons of its night sky illuminating the shadowed paths of its majestic forests and shining down on its stunning mountain peaks.
The major thrust of this exploration of the world will be known as The Soulseeker Campaign. All of the action and intrigue will take place within the borders of an expansive empire called the Imperium. And while it may seem like a stifling, constrictive part of the world, the Players should be prepared to grow into truly powerful heroic figures that can challenge and perhaps even change the stranglehold that the military dictatorship has on its territories and its citizens.
Soulseeker Campaign - Six Truths
1. The Imperium's influence and reach is impressive, frightening and ever present. It does not take much for its iron fist to squash you should you dare oppose it, or break its laws.
2. Whispers of rebellion have always floated hither and thither, only to break apart with the mildest of breezes... and yet only one needs to take root in order to grow into something wind resistant.
3. Something dark and dire is approaching from the West. Word has come back from the borderlands that outposts and garrisons are being overrun.
4. A secret once lost has been rediscovered, and there is a man in Stormhaven who very well might hold the key to changing the fortunes and fates of every living soul in the Imperium.
5. There are thin places in the world - thin, dangerous, and mind-altering. Everyone has heard tales of those unfortunate souls found wandering alone, muttering, drooling, claiming to have visited other worlds, other whens.
6. Delvers and Slayers of all stripes can find fame, fortune & glory - if they survive long enough.