From what little research Rui had done, it was said that the Thundering Valley was used by Martial Artists from across the continent to test their Martial prowess. One thing Rui was relieved by was the fact that the Thundering Valley was not as densely populated as the Umiana Trench.
The latter necessarily needed a huge number of Martial Artists in it at any point in time. However, that made it more unpleasant for Martial Artists like himself. Most Martial Artists preferred to train in solitude, thus mass training was something most of them had not done in a long time; since before they even became Martial Artists in the first place.
Rui had to admit that the fact that training in the Thundering Valley was not regulated by some organization was quite relieving. He knew that there wasn't as much of an issue just entering and doing as he pleased without some Valley Surveillance Force getting on his back for every little thing.