The origins of the Nine Tribulations Sword!

"The continent's dispute had reached the point where, if it wasn't curbed in time, then it could lead to a thorough destruction. Thus, the nine great powerhouses relinquished all hostility and friendship towards each other, and gathered together to have a discussion and eventually reached a solution for the situation at hand. And that solution was: the continent would be divided into nine big chunks, including both barren and fertile regions… in this context, the barren and fertile regions are referring to the regions with… low and high content of 'World Vitality' respectively!

"They mutually agreed upon assigning one region to each of the nine races. Afterwards, they could only reside within their respective regions. If any of the races were to ever try and cross the border, then they would inevitably face a joint attack of the others.