Alright, here's my pitch for some world-building, retaining some 5e lore.

[i]Enclosed between two rumbling titans, the Realm trembles in fear and anticipation, as mighty relics encroach once more.[/i]

[hider=Terrible Footsteps in the North]
Giants once ruled the world, the mightiest beings that far predate elves and entered the world when even dragons were young. All giants originate ultimately from a single entity, being descendants of the God of Giant and his consorts from various races. Giants were conceived as masters of the world, birthed from the elements and given great height to look down on all they ruled. The giants set up an expansive empire, Ostoria, stretching to nearly every corner of the globe and trampling over any resistance with what they saw as their divine right to rule. Their empire filled the sea, and castles topped mountains and even clouds. All they observed was their dominion, and all creatures paid homage to them. Needless to say, the existing inhabitants of the world protested to this change in management.

Dragons -hardly saints in their own right in many cases- rose up in defiance with other races behind them. It wasn't for any single reason that they fought, but rather a culmination of things, and all it took to finally ignite the flames was the right charismatic and ambitious leadership. The metallic dragons fought for peace and liberation. The chromatics fought for greed and dominance. Yet, together, they were united in the purpose of ousting the giant overlords. The war they waged shook the world in what would become only whispered of as the Thousand-Year War. It was a brutal, lawless free-for-all of winner take all. There were no front lines or safe havens, only endless ambushes, sieges and atrocities committed against both sides.

In the end, none were left alive that remembered the war's beginning, and many had lived their entire lives in war. Both giants and dragons were shadows of their former selves, so reduced in number that even sustaining a population became troublesome. The great war did not end with a bang, but withered out with a whimper with no clear victor. The giants managed to preserve their capital, Voninheim, far to the north, but their dominion of the world was forever lost. In the face of this humiliation the Giant God forsook the giants, swearing to never look upon them again until they had reclaimed their birthright.

To this day, they have failed to, though not for want of trying. The giants remain expansionist, yet humbled enough to show restraint and patience. Their poor birth rates and need for large amounts of resources to sustain their kind have kept their numbers low even centuries later. While there is no doubt the giants are a formidable world power, they simply lack the ability to hold anything they might conquer. Yet, even the long memories of giants fade in time, and the more ambitious among them had been pushing for more aggressive action, impatient to reclaim their lost glory. Small groups of rebels strike out as raiders to other lands, creating tensions and mistrust towards the rest of their kind. Yet, the giants have publicly denounced these elements as bandits and criminals while not doing anything about them, a state of affairs the rest of the world begrudgingly accepts for the sake of avoiding full-scale war. The rumblings of conflict tremble distantly through earth and prophesy, and the world seems subconsciously on edge, awaiting the spark that will send the unified Ordning marching to war once more.

The Giant God established an innate, instinctive hierarchy within the giants -called the Ordning- that generally ranks giant types: Storm, Cloud, Fire, Ice, Stone, Hill, Ettins, Giantkin (Firbolgs, Verbeegs, Fomorians), and Orges, in that order. Even the highest member of one segment of this caste social structure is still lesser than even the lowest member of a higher caste; even the Hill Giant leader is lesser than the lowest Stone giant. Despite this, discontent with this system is strangely rare among giants, and few do not simply align with it without question. Giants know that they are all kin, brothers and sisters in blood, ultimately united in purpose, and they accept that each giant has innate talants and weaknesses, and a place in their society that they are most suited to inhabit by birthright. Therefore, giants promote a culture of acceptance and laud mastery of each giant's "role", which directly contributes to their rank amongst their caste.
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[hider=Scaled Terror in the South]
In the wake of the Thousand-Year war, dragons were scattered. In a way, it could be said they lost the war, but the goal was accomplished. The giants had been laid low, the favor of their god lost, and their dominion of the world almost entirely erased, the remnants having mostly congealed into one unified front in their capital. The dragons, meanwhile, took flight to all the corners of the earth, having not been much for civilization building prior, doing their best to simply survive and regroup. Even centuries later, dragons remain independent and territorial creatures, rarely uniting under a common banner due to pride. Dragons, much like giants, typically see themselves as inherently superior beings, born rulers, and they are loathe to tolerate any authority over them, not even another dragon.

The Draconic Empire was born from the exception to this rule.

Located on an island nation to the south, far from the giants, this imperial country was established by a coalition of primarily chromatic dragons. A few metallics number among them as mediating influence, but most metallics lack the patience to tolerate their tyranny. The dragons have established a country that from the top down is intended to serve the dragons desires above and beyond all else. As such, the greatest concern of all inhabitants is The Tithe, a periodical tax of wealth and goods to be sent to the hoards of the ruling dragons to appease their greed and hunger. Dragons, having an innate mastery of wealth through their perfect memory of their hoards can pick out even the slightest discrepancy in this Tithe and will levy destructive punishment upon any that attempt to cheat them. For the inhabitants of the Empire, the Tithe is a literally a matter of life and death, and any disruption to it is subject to the most capital of punishments.

The Dragonborn, the acting regents and rulers of the Empire, organize the Tithe and the country. Dragonborn maintain vast coffers, containing the wealth of the land, and they often build up reserves of wealth to compensate for any faltering in a settlement's taxes. After all, regardless of their culpability in a discrepancy, they prefer not to risk being lumped in with the culprits and handle punishing  those that lack in a more "internal" manner.

In the meanwhile, the Empire cultivates not just its own wealth, but also seeks to take the wealth of others. After all, their nation only has so many resources to give to the black holes of the dragons' hoards, and so, to stave off collapse, they range outward. The Empire therefore maintains a navy, arguably the greatest navy in the world. The southern seas are the domain of the Imperial Navy, claiming vast swathes of the ocean as their territory and raiding and sinking any ships they come across that cannot -or refuse to- pay a heavy tax of a percentage of their cargo. Sea trade is considered extremely risky business, and while the Dragonborn have not yet resorted to outright land raids -that are sure to incite war with other nations, if it considered to likely be an inevitability.

The Empire is ruled by a caste system that dominates all and shapes every inhabitant's worth in society. Unlike giants, however, blood is not everything; for dragons are far more meritocratic, putting great value on cunning and leadership. This meritocracy ultimately leads to a competitive air on a societal level, where the competition is who is the most "useful" to the Empire. No matter what your "base" rank, it is theoretically possible to be considered higher on the totem pole through sheer merit. Dragons sit at the top, followed by Dragonborn, Kobolds, Dragon Turtles, most other sentient races and Wyverns, in that order. Despite the flexibility a meritocracy provides, in practice, the caste system is the rule, and each caste is jealously protective of their rank, going out of their way to sabotage any "upstart" from a lesser caste while working to undermine higher castes for greater influences. At the pinnacle of this system sit the Dragonborn, who have dominated all comers, acting as the functional rulers of the country. While the Dragons ostensibly hold the highest authority, their aloof, reclusive and lazy nature leads to them being hands-off as long as the tithes keep flowing uninterrupted. As such, the Dragonborn treat them as figureheads and go to great lengths to keep anyone from making contact with them but themselves, acting as a filter with the outside world. The Dragonborn are therefore the unquestioned tyrannical rulers of the Empire, and they mean to keep it that way.
[/hider]

I admit, I'm struggling to come up with an actual proper name for this possible dragon empire. Something with "Imperial" in it maybe.