Shan Liangyi in his prime possessed the power to open the third door, but the current level of Shan Liangyi is still an unknown.
The Power Seeds possessed by the Liangyi Inheritor are derived from the power inherent in Shan Liangyi himself. According to knowledge Liu Shuying somehow obtained, if the current Shan Liangyi only possesses the Earth Element Yellow Dragon Power, then his strength might only be at a normal Impermanence level.
"Normal Impermanence" is a term that sounds off when heard. Anyone who can become an Impermanence is an unparalleled miracle between heaven and earth. Each Impermanence is unique, and there is no such thing as "normal." However, I somewhat understand the meaning Liu Shuying wanted to convey. What Liu Shuying called "normal Impermanence" refers to someone who has reached the expected maturity level of strength in both scale and density.
