Xiao Yan had once coincidentally read that the Ground Rehmannia Glutinosa was formed by gathering the heavy and calm essence of the land from a medicinal ingredient book that Yao Lao had left behind. However, there were limitations to its growth. Any Ground Rehmannia Glutinosa would not continue to grow in size after a century due to the lack of energy. This was also the reason why Ground Rehmannia Glutinosa over a hundred years old were so rare.
Based on what was recorded in the ancient book, if a Ground Rehmannia Glutinosa was able to grow far beyond a century old, it meant that the thing nourishing its growth was definitely not the strength of the land. Instead, it was some other natural spiritual object!
Xiao Yan understood his heart after having laid eyes on this Thousand Year Old Ground Rehmannia Glutinosa. There was definitely something else underground. Moreover, it was this thing that had nourished the Ground Rehmannia Glutinosa.