"If water is the foundation of life, then it goes without saying that the quest for immortality should start there as well." This ancient saying passed down from elders to juniors since time immemorial, defined the Qi Refinement and Foundation Building stages. The Qi Pool condensed through the accumulation and merging of Spiritual Drops pretty much decided whether or not junior experts had a shot at the Golden Core and Nascent Soul stages. And if there was one thing that talent—no matter how high—couldn't defeat, it was a shallow foundation.
For that reason, elders of the cultivation world paid close attention to their young and rash juniors' Foundation Building—never allowing them to cross that threshold unsupervised. And to make sure that their juniors knew what to aim for, they divided the Qi Pool into four tiers: Shallow, Regular, Profound and Heavenly.
