I am super excited that people are into their characters to the point that the history of their land is a factor.
I'm not sure how I ended up resident expert on Tian Xia since I tend to make things up as I go, but I'm assuming Frug simply wants to share the wealth {workload} with others as far as the environmentals go here. The reason I picked "Gur'yeo" to develop is because its a very, very small percentage of the Tian Xia population and I could go into great depths without having to write a thousand page manual on what Tian Xia is. Also, Korea is just cool.
At anyrate, until we get more solid stuff written down, its open for discussion. Keeping your character referring to things in generalities would be the safest bet, and I have been loosely basing Gur'yeo on medieval Korea and historical patterns that would probably create similar situations in this setting as they did in the real world. That being said, I've written Gur'yeo to be clashing with the larger state of Tian Xia. I have also been going off the assumption that the ancestry of all Tian Xia people are of some "mongoloids" who would have been Genghis Kahn and his line.
The way I envision Tian Xia is that it is not made of states or politically drawn lines on the map for the most part, but regions which are controlled by clans, who have fallen into a rough alliance to form their Empire. They had warrred with each other as humans are prone to do up until the rise of the Tian Xia Changer who managed to encourage the majority to work together and fight for him. (The Gur'yeons, being isolated on the far reaches of the continent, decided not to waste their fighters in the distant war and could not be persuaded to send warriors to support the Changer.) I imagine the population still has not recovered from the War, and so sparse population affords some clans to roam nomadic and some to live in set areas without much border contention.
Each region pays their respects to the Emperor, monetarily (although this is more of a symbolic gesture and not designed to sustain the Emperor) and politically by allowing him to be the ruler. Going again with a roughly Asian belief system, the ruling pedigree is believed to be of the Changer's bloodline and holds a theological aspect as well as political power. Frug and I discussed this in chat the other day and I think we came to a consensus that for this time period, the Emperor is actually a competent, active ruler and the seat of the Empire has not yet been reduced to serving as a mere figurehead for the power-hungry. He does not view himself as a god or a king, but more as a servant of his people and desires to maintain the current peace between all of the clans. As such, he has not made any drastic moves to mandate that any one dialect is adopted or that taxes be imposed on the clans or any other policies which could otherwise upset the heads of the clans and give them cause to attempt a coup. He is generally liked, and the population in certain regions has been slowly increasing. This, of course, means those people are becoming more prosperous, comfortable, and idle.
Well, I hate writing stuff like that but there's the beginning, a skeleton from which we can work from. Always open to discussion and suggestions. And of course if I'm way of base I'm sure Frug will take the appropriate editing axe to it.
) please correct me here as I have tended to assume that era as a rough guide to how things are (obviously keeping the Changer's war and etc. in mind 
