The Times Have Changed!
Although Qing Qiu and the Great Xia Alliance stood on either side, dividing the north from the south, that did not stop the various clans of the Four Seas and Eight Desolations from traveling between them.
What was more, the Eight Desolations were full of waterways, so it was impossible to create an absolute divide. They could only prevent armies from passing through.
The great clans of the Four Seas and Eight Desolations had all intermarried, and they had passed word along about conditions in both the north and the south.
So, when they learned that the north was peaceful and tax-free, while the south had been engulfed in war for years, many small clans realized they had no way to protect their own heavenly treasures and earthly jewels. They would only be used as cannon fodder if they stayed, so they sold their treasures to the Wing Clan and moved away.
The Wing Clan was already struggling with internal troubles, so it didn't dare force these small clans to stay. They feared that doing so might offend either Qing Qiu or the Great Xia Alliance.
It was under these circumstances that Tuan Tuan began slowly building cities to the south. Whenever the Great Xia Alliance finished building a major city, it moved the people who had originally fled back there, quickly taking control of the area.
After each city was completed, the Wing Clan didn't dare take even one step beyond the Thunder Pool, which made the returning people feel much safer.
Under these circumstances, more and more people began asking the Great Xia Alliance to build cities. Many even joined in themselves, making the construction of cities ever faster.
By then, the great clans of the Southern Wilderness, which had been fighting for centuries,