In the Immortal Cultivation Sect, the protagonist is bound by many precepts, like a imprisoned bird. If you get up early in the morning and are late for refining Qi by one second, you will be punished by sweeping away the spiritual field which smells strangely and is often visited by spiritual animals causing trouble. Life is very frustrating.
So the protagonist shouted "I want to be free", so on a dark and windy night, he secretly left the sect and embarked on the path of casual cultivation...