A late antiquity/early medieval fantasy world is struggling with the collapse of its greatest empire, the ancient Empire of Umprinorous, collapsing from the owner of the whole sea to a rump state and a bunch of warring barbarian states. As rival claimnants to the Umprinoran legacy attempt to pick up the pieces, mysterious unidentified flying objects bearing strange green men attack. The emperor of the aforementioned 'rump state,' now a regional power, has set out on a quest to get everyone to put aside their differences just this once. Can the warring factions unite against the alien menace, or will their rivalries successfully be manipulated and these great fantasy kingdoms taken down, one by one...
WIP
The world is essentially divided, or at least the known and plot-relevant world, into a variety of smaller kingdoms, that project rough but hard power from either urban centers or forts depending on the terrain and historical urbanization of the region. Many of these are tributary to the three major powers: First is Umprinoros, the last remnant of the old empire. Based very heavily on the IRL Medieval Roman Empire, known to itself as Romanía and to a far-too-high number of westerners as 'Byzantium,' it likewise has a quote-unquote monarchy that is more like a limited non-hereditary executive-for-life, though many individual emperors may try to promote their own dynasty. This leads to more meritocracy as old families are not valued just on the basis of dynastic prestige, but leads to instability as if anyone who is strong enough can take the throne, a lot of people will. Still, its emperor during the time of the setting, whose name is tbd, is the main character of the story and his ability to survive all of that is not only another source of conflict but is what builds him up to be able to handle the game of international realpolitik so well in this time of crisis. The other two empires are not as well worldbuilt, but they also claim the legacy of Umprinorous. The first is what is essentially a Viking HRE founded by a cross between Charlemagne and King Arthur. Like the HRE, it is essentially built of a bunch of quasi-independent lords who operate on their own and occassionally war with eachother but are protected from losing their entire 'birthright' by the emperor, who is 'elected' by the most powerful lords through an assent/dissent system. They also have a strict code of nobility, but this chivalry is not exactly humane, though it does prevent the society from collapsing in on itself due to excessive violence. Like the vikings, however, they have what essentially amounts to a holmgang tradition, a martial afterlife, and justify raiding to themselves. It is greatest in life, after all, as the saying goes, to"crush your enemies -- See them driven before you, and to hear the lamentation of their women," as long as those enemies are foreign and not worthy of the glory of Ombrinoresc. Finally, we have oligarchic samurai crusader Mongols. Samurai in that they use katanas as their primary form of sword and have a warrior class whose gender role divisions are strict and amount to "men don't do finance, women only do finance," and that they embrace the idea that the lower class exists to serve the other rather than the other way around. They are crusaders in that their motivation for conquest is religious, being monotheists who believe their one god told them to conquer the whole world in His name so He can drive out the demons other cultures regard as 'gods.' Like the Mongols, they are horse-riding steppe warriors who believe they are a chosen people destined to bring peace to the world by uniting it under one country, their empire, and are effective particularly because of their innovative uses of horseback warriors, in this case having 'horse-mages' who cast fireballs and lightning and magic missiles while riding. They are oligarchic in that their political structure is decentralized, with the hierophant being more of a nominal figure as holy orders consisting of a group of 12 or so baghāturs (placeholder name for the upper class of horse-riding warrior-archer-mages that are the core of their power, based on what CK3 says the steppe equivalent of knights are) basically formed exploitative governments wherever they decided to settle down after conquering, without paying taxes to any central authority, only listening to the decrees of the central hierophant they 'determine to be true and legimitate,' and only contributing military forces for attacks from outside that might potentially harm the order. That being said, these orders are like bands of brothers within themselves, them and God against the world, and thus have little infighting among the upper class which is part of how they are able to remain in power despite being the most exploitative to their conquered Umprinoran and formerly-Umprinoran subjects. A sub-hierophant has recently been voted in for 'The nation of the Aumprinorai' but it remains to be seen how long that will last