The Wood Refinement Demonic City was created by a child of Immortal Emperor Mu Zhuo from one of his many lovers. Mu Zhuo himself never entered the City, but he left behind many techniques and even his Immortal Emperor True Treasure. However, Mu Zhuo did not left behind his Grand Dao, thus some researchers believed that Emperor had not recognized the Wood Refinement Demonic City as his lineage and it is only a side branch at best.
However, Immortal Emperor Mu Zhuo's direct lineage disappeared along with him and the imperial queen. Due to the silence of the main branch, the Wood Refinement Demonic City was able to claim position of Imperial Lineage without any backlash from the public and people easily accepted its status.
Anyway the Wood Refinement Demonic City became a great lineage in the Grand Sea, among the top of the rankings for millions of years. It was an ancient and sacred city, especially in the heart of the Demons. The City was prosperous with billions of inhabitants. It passed on for one generation after another with the same riches. They had to be praised for having the proper administration.
The Wood Refinement Demonic City was majestic with towering walls and spanned for ten thousands of miles. This gated region seemed to be its own world.