Cultivation was not just to increase one's strength but also their mental fortitude. Thus, the importance of cultivating one's mental fortitude went without saying.
Be it Qi Refinement, Foundation Establishment, or Golden Core, they were all cultivation realms inclined to one's strength. However, after the Nascent Soul stage, the cultivation of one's mental fortitude became even more important—one had to experience the mortal world to train their mind.
If the cultivator firmly believed in their own Dao, they would naturally be able to advance by leaps and bounds in the road of cultivation, improving greatly in a short period. However, if one started to doubt the Dao they had chosen, then mental demons would be easily formed and result in serious injuries.
One's Dao need not be of the Five Elements or Yin Yang. It could be something minor, such as the Dao of musical instruments, painting and calligraphy, or even the Dao of admiration toward powerful beings.
