Alchemists are a specific type of scientists, who deal with human flesh. While this may sound terrible, they are essentially doctors who has studies the natural spiritual energy of the world, or magic. They cannot necessarily utilize magic, however they are usually knowledgable within areas of manipulating natural energies of the world, in order to accomplish their goals.
It is said that the ultimate goal of Alchemists is to create the Philosopher Stone. However, many believe this is merely a legend.
Alchemists believe that the same type of energy that the Philosopher Stone is said to harness, can be found within all living things.