So, here is what I am thinking:
The characters are from the area in Breland that sits in between the Whitehorn Wood, the Dragonwood, and Castle Arakhain. From my looking at the population numbers in Breland, and a thread I started in the General Forum, it has come to my attention that the number of people that live in this area (roughly a 50 km radius of the starting town) is likely to be astounding: five large towns, theoretically ~500 villages, encompassing upwards of 250,000 people. In any case, each character hails from a different village, and at the beginning of the game they will all have been summoned to the central town, which is how they meet. The important thing to note is that the origin and location of the characters is not meant to be a limit on what this game will be like. It is primarily meant to be a sandbox game, and if the characters do not care for this area at all, they are free to go somewhere else to find fame and fortune. I am merely provided a framework to get things off the ground.
In any case, the theme of this area is one that is finally getting a chance to sort its affairs out. The Last War has meant a lot of things have been put off for a long time, and only know are the resources becoming available to clean things up. There might be bandits to put down, mysteries to investigate that were once unimportant, ruins to to explore that have not been touched by the authorities in nearly a century, and just in general to clean up things that have been allowed to fester as men and resources have been tied up fighting an all-out war. Perhaps also new threats that are having a chance to emerge now that military vigilance is being to wane.