The God-Slaying Saber said, "Actually, beyond the Tongshen Formula, cultivation methods no longer exist. This is because cultivation methods merely tap into the potential of the physical body, whereas after a cultivator breaks through to the Celestial realm, the first three stages focus on the integration of essence, qi, and spirit, uniting flesh and soul.
"Starting from the Fourth Layer of Celestial Human, however, the focus shifts to the comprehension of rules. No matter how powerful a cultivation method is, it cannot touch upon rules. Therefore, strictly speaking, whatever level of comprehension you have attained regarding the rules determines the tier of cultivator you are.
"Yet, as I mentioned earlier, supreme powerhouses created cultivation methods and divided the realms, just as other powerhouses attained enlightenment of destiny and established certain rules."
Chapter 425