Dawn of Adventure
While not necessarily a nation, Capitol city is likely the largest city in the world (the only reason I say likely is because the city is so large, no proper census has been conducted in centuries). It lies near the center of the continent of Orin, on the border between the Sunlight Empire and the 9 Cities. Almost 1100 years ago, near the end of a major war between the Empire's and the Cities' predecessors, a small border region was declared independent from both powers as a place to house refugees from the war. Over the next thousand years, this relatively small plot of land has grown into a massive city where people of all races, creeds, and alliances come together for trade and merriment. The city is protected by a huge number of defensive spells cast on it over the centuries. Such is the sheer number and power of these spells that the city is considered by all to be completely unassailable with anything short of deific levels of power. Direct conflict, unlicensed spell casting, and any form of fraud are strictly prohibited, and performing any of these actions can lead to an individual being permanently banished from Capitol, essentially meaning the cities magical defenses are tuned to consider the individual just one more enemy. It is said that anything any mortal could seek can be purchased in Capitol City, as long as the buyer has the gold available.