Khymeiasts, or in the language of Modern Society is called Alchemists, are groups of humans who have the ability to use the ancient art of alchemy, fusing metals, changing its molecular composition based on the laws and altering the properties that could comply with their necessities.
At first the people perceived Khymeia (Alchemy) as a magic, that is why Imothep , the very first magician, was believed to be the very first khymeiast also. His greatness first spread throughout the ancient civilization of Mesopotamia. There was once a man who visited them and introduced to them the greatness of His magic. Seeing this, the mesopotamians imitated his craft and the first lineage of alchemists could be traced down from their community.
However, some people did not accept Imothep's contribution to improve Mesopotamia's growing economy, that's why he went back to his homeland, Egypt, to spread His magic.
Later on when trading has begun among different civilizations, the concept of Khymeia went to the Greek people. In this place, it is not treated as magic anymore, but an art (science).
In the age of Roman empire, it is already called as "Alchemy".
Throughtout the story there are several people who could perform alchemy. Some people like to call it magic. Some would prefer it is a special kind of science.
Jett Towerlocke is one of the Seven Keys that opened the Gates of Eden. Following the story, he is just an ordinary human, envious of his comrades who have abilities, unlike him. But later on, it is discovered that he has the blood of Imothep in him, and that alchemy is a natural phenomenon in his life.
His category is at Advance Alchemy.