Wei Lang, the great white wolf

Only Moonstone can terminate the soul binding vow.

For centuries, the men born in the Wei bloodline believed in that truth and searched for Moonstone. Under the effect of his inner wolf, Tang Wei Sheng also wandered across the mainland, searching for the precious stone which could calm the Wolf God and end his agony. 

The unification of the mainland was just a subsidiary plan of his long term goal, a way to hide his true motives. 

While studying in the Huo sect, the flaming fire sect in the East, he accidentally heard his master mentioning the location of the moonstone. 

Moonstone was hidden in Yu kingdom, a region that remained untouched by the political dynamics of the mainland. It was the largest repository of gemstones. However, instead of using its power to rise into a prominent figure in mainland politics, they remained hidden behind the giant mountains, saving their repository from the enemies.