Learning Fate Core, sword and sorcery fantasy setting
That's all fair advice. I had not considered how play by post could slow down the process and risk attrition.
So here's a start. It's a bit more than broad strokes, but it can all be tweaked while providing ample base material to build from.
There are seven nations which occupy the continent of Talan, each their own sovereign though in times past the borders were often negotiable and more than one would-be emperor set his sights on uniting the seven nations under one banner. Some legends claim there is another continent, from which came several waves of settlers to Talan, but no one now knows its location. Talan is a land of diverse cultures and histories - and more often than not their histories are at odds. It is a land of merchant lords, pirates, knight baronies, reclusive monasteries, adventurer scholars and robber kings. Too there are castes - the Warrior, the Scholar, the Peasant, the Clergy, among many others, which share common codes, beliefs and even loyalties among members which can sometimes cross political lines.
Social status is separate from caste, though often the highest rungs are closely associated with one or a small number of castes within a given nation. Honor is highly valued regardless of nation or caste, but the definition of what is honorable also varies from nation to nation, caste to caste. Status is also tightly bound around one's accomplishments rather than one's ancestry. Most cultures within Talan are highly patriarchal, with a tremendous disparity in the rights and social expectations between genders. Suggesting otherwise would mark a person as simple or naive. But even the lowest offspring of members of the most humble castes have pride, honor and free will. Slaves have none of these, and the institution of slavery is commonplace throughout Talan. Indeed, it is considered one of the more practical spoils of a defeated enemy, and one of the better reasons for conquest.
Concurrent to this setting of politics, war, skirmishes, intrigues and other social dramas there are those things which are inimical to all: Dark Ones. These creatures are the stuff of both legends and horror stories told to children to keep them in line. Some are almost ubiquitous, like the goat-snatching bunyip. Most are mysterious, unknowable, like the ghostly Grimbane which monthly hunts the largest of cities like a well-laid buffet.
Magic is likewise prevalent, but mysterious and unknowable. Few are those who can claim to know it, and all such are viewed with distrust. There is no caste of magicians, or schools where magic is taught, but no one doubts the existence of magic. It is both subtle and powerful, and almost always dangerous to those who callously call upon it. There is a tremendous body of myths and legends regarding magic. Second only to the stories of Dark Ones are the cautionary tales of men who sought to use magic and were destroyed. Or worse.
In frantic waves, messengers of the Herald caste spread the word: almost a month past, Malarai was destroyed. A population of millions simply disappeared, along with its great stone palaces, brick and slate roads, warehouses and docks, cathedrals and caste halls. It is as if a giant hand scooped the city and all its contents from the earth - but no one saw it, can explain how it came to be. In a moment, the span of a breath, it was gone. The largest of the cities in the eastern nation of Markand and one of the most powerful city states in all of Talan, the great city of Malarai left a vacuum of power and a tremor of fear throughout the continent. The Presidi of Markand issued a call for heroes to investigate the outlying villages and the vacant, ruined crags left remaining in search of answers. Rulers and caste leaders throughout the continent are gathering their resources, tightening their borders, shoring up reserves, with one eye towards Malarai and another on their neighbors.
This is not necessarily that story, but it is a very tumultuous time in Talan.
I'd like to have at least four players before starting, with the hope of gaining a couple more before the story gets rolling. If everyone here would still like to get this rolling (please reply!) then I'll put on my GM cap and start it up.