Thinking about this, Qiu Tu couldn't help but recall the situation surrounding Yaksha.
Based on the intel Qiu Tu had interrogated out of Muye over the past two days,
the "Fog Hidden Association" is a secret organization rooted within the "Boundless Heart Sea - Core Region." They likely command significant resources in the "Core Region."
And among these resources... is the special Cataclysmic Material known as the "Mountain Root," produced exclusively in the "Core Region." (Chapter 465)
The primary function of the "Mountain Root" is to bypass the restriction on advancing to the Sixth Rank. As such, the "Fog Hidden Association" generally smuggles "Mountain Root" out of the Core Region to help its members advance.
