The game is currently being discussed in this thread. Now that the core rules are nearing completion, I'm starting to think about a setting . . .

The Empire of the Moon and the Stars had long been at war. The Five Kingdoms faught for decade upon decade. Vast armies of peasants uprooted from their fields and given a pole-arm clashed endlessly. Eunuchs and priests paying homage to dark spirits used the chaos to carve out a niche for themselves in a troubled world. But finally, after a century of turmoil, the Empire is at peace.

The Rolling Kingdom, a lush land of green fields and gently winding rivers, lies at the center of the Empire, for it is the Moon. The Southern Star is the Burning Kingdom, a fiery desert that sloaly broadens every year. The Northern Star is the Crystal Kingdom, a winter wonderland of snow covered hills and peaks. The Eastern Star is the Bamboo Kingdom, thick with forests of leefy green and secluded shrines to the nature spirits. The Western Star is the Iron Kingdom, filled with towering, craggy mountain peaks, the valleys inbetween sharing their bountiful harvest with the high monasteries of the Feng Jin monks.

After the great wars came a time known as the Three Hundred Year's Peace. Yin was balanced with Yang, and the elements stood poised in beautiful harmony. But now the Three Hundred Year's Peace is ending: travelers speak of the Iron Kingdom erupting in flows of liquid fire, they bring news that the Burning Kingdom grows faster every year. The Rolling Kingdom is shrinking, and the Emperor is losing sway. Seers speak of planets shooting out of their orbits and roaming lost in space, and the plaguing bandits make even short travels a danger. Foul spirits infest the forests of the Bamboo Kingdom, and it is rumored that the Eastern Star plans to abandon the rest of the Empire.

It is a time of unbalanced Yin and Yang, of clashing elements, of the end of peace, and the beginnings of war. The Five Kingdoms are drifting apart, and the Eunuchs are coming back into power. Only a chosen few have the power to resist . . .

Comments and suggestions appreciated.

Are the Kingdome simply called Stars, or are they really celestial bodies? I can see either being interesting to play in, but the second would make for distinctly weird game.

As for the unbalance of Yin and Yang:
It seems that there's an increase of Yang here, or that the Yin in the affected kingdoms is suddnely "tainted", causing chaos and destruction rather than suppressing the out-of-control manifestations of unchecked Yang. What I'd like to see is a greater unity of effect here, and more importantly a way to tie characters to the setting. Like, if my first hypothesis is the case, then you might see:
The Burning Kindom's growth accelerates, eating into the edges of the Bamboo Kingdom, whose own growth is suddenly choking the borders of the Rolling Kingdom with eldritch plants.
Meanwhile, the frosts of the Crystal Kingdom are receding, and the Iron Kingdom is racked by constant quakes, which pull down the high sanctuaries of the monks and round the edges of the mountain peaks.

But, why do the characters care? Is the Emperor executing the Bamboo Kingdom idol-priests because he blames them for the weird infestations? Are the Snow Witches stealing children to try and moisten the land with their tears?