After level 11, the breathing technique seemed to have reached a watershed. Its dependence on secret medicine increased further. Without secret medicine, it was difficult to cultivate the breathing technique.
Levi felt that the secret medicine would be the key to his breathing technique cultivation. After becoming a legend, the materials needed for the secret medicine needed to be updated. Many of those mortal materials needed to be eliminated and replaced with extraordinary materials with similar functions.
If one could still rely on ordinary secret medicines to cultivate before becoming a legend, then after becoming one, if one wanted to gain experience quickly, one would need corresponding extraordinary secret medicines. Moreover, simple concoction was no longer possible. The next secret potion might require Levi's pharmaceutical knowledge to carry out the refining.
"Fortunately, I'm a pharmacist. This is my forte."