Spirit Root
As Davis read on, he stumbled upon the real and authentic way to measure one's talent.
Apparently, there is a particular root existing within the Dantian.
That root was known as the Spirit Root. The manifestation of a person's talent from birth.
At this point, Davis became astonished before he surveyed his own Dantian. He used his essence energy to probe around but couldn't find anything that fits the description. He even used his soul sense to stay every inch, every corner, but he was unable to sense that so-called Spirit Root!
The only powers within his dantian were the stable yet deep black Revolving Core, and the manifestation of the torrential rain of black lightning in its dormancy, ready to erupt when used in battle.