The ultimate goal of ancient Xingese Alchemy, it was believed to allow the alchemist to achieve their goal of simulation of the world inside the mind. With the Elixir of Life, they can bring out thoughts into the real world; essentially, making those who can accurately simulate or mold the real world would be able to control it.
However, since Xingese Alchemy was an unrefined knowledge, modeling the entirety of the world and its laws was found to be nearly impossible and lead to the loss of many lives. Hence forth, no one was ever able to achieve the Elixir of Life before the foundation of Alkahestry.
Luànmâ is the only person who has managed to achieve the Elixir of Life. By thinking of it as less of a alchemical technique and more of a martial arts meditation technique, and even then it didn’t follow its original intended use. In his/her use, the Elixir of Life distorts reality through his/her thoughts, and requires a vast amount of concentration and energy to accurately model a thought into reality with it.