Ancient Xingese alchemy was built on the practice of making a natural body into perfection. Or simply put, humans are incomplete gods and through training and making one complete, humans can become gods. Xingese Alchemy focused on the discovery of the Elixir of Life its goal was to simulate the entire world; any result that they happen to get before reaching the ultimate objective would, or should be seen as useless by the alchemist .
This lead to a series of misguided attempts at mystical healing through the ingestion of various substances. In fact, it is said that three whole generations of the imperial family died from ingesting mercury because they believed that it promoted longevity.
When Alkahestry came to be the ancient ways were soon abandoned. Modern day Wu are seen in the same light as Sheska civil servants whose job it is to recreate and keep accurate documentation of ancient ways in Zhōng Yèshū. This is why being appointed as a Wu is considered more of a death sentence then a privilege. Wu are mainly used as test subjects and rarely survive for long.