However, Old Zhang's method of producing the Samadhi True Fire does not require so many resources.
This method, discovered by Old Zhang through alchemy, starts with turning oneself into a Human Pill.
It can be said that trying to produce the Samadhi True Fire using Old Zhang's method does require a prerequisite: proficiency in the alchemy technique.
The reason why Cao Zhen taught Yi Sheng that special cultivation method back then was to prepare for the future when Yi Sheng would attempt to produce the Samadhi True Fire.
As for Li Ke, Li Ke isn't particularly skilled in alchemy.
As long as Yi Sheng breaks through and enters the Immortality Regainment Realm, Li Ke will naturally be able to produce the Samadhi True Fire.
