A Sage has already grasped the essential Dao Principles of a certain field. They can create new sub-categories within an existing framework and even devise new techniques in the heat of battle. Such a realm is sufficient to establish a sect and be remembered by later generations.
Higher still are the Grand Sage, the Quasi-Supreme Grand Sage, and the Supreme Grand Sage, each level further and further removed from ordinary cultivators. A Grand Sage can infer the whole from a single part, having almost completely comprehended a given field. A Quasi-Supreme Grand Sage has exhausted the mysteries of that field, their skill approaching the Dao itself.
A Supreme Grand Sage can create entirely new major categories, pushing the upper limits of an entire school of thought. Which of these realms did not require long years of accumulation? Which did not demand repeated failure, reflection, and enlightenment?
Ning Zhuo already felt that his progress in comprehending the Demonic Blood Vein Technique was slow, but that was, after all, still the practice of a cultivation art. The advancement of one's realm was an even longer, more arduous process.
It was like sand settling at the bottom of a river, accumulating day by day, only for a new riverbed to be revealed when a great flood washed through. The most vivid example before him was the Pure Yang Ancestor Pill.