Formation, alchemy, and artifact refining are all one of the four major secondary professions in the Cultivation Realm, also divided into nine grades down to the first grade.
After absorbing thirty years of experience in formations, Han Li became an Eighth Grade Formation master, capable of setting up some simple basic formations such as Spirit Gathering Arrays and so on.
If he had the corresponding level of array diagrams, he could also set up an Eighth Grade Formation that could contend with the Pihai Realm.
Formation, alchemy, and artifact refining were three skills that Han Li was not yet very proficient in, at only Eighth Grade, which were not very useful for him, yet they were extremely beneficial for his concubines and the Han Family's descendants.