Alchemy refers to the practice of altering the chemical makeup of matter to obtain different chemical compounds. Most examples of alchemy involve some form of magic component to perform this process.
In Real Life, alchemy was a forerunner of chemistry and the medical sciences. Alchemy was in practice well into the 18th century, but most of its ideals were proven to be physically impossible upon the discovery of the composition of matter in terms of the atom. Elements of alchemy were common in almost every ancient civilization, including the Greco-Roman, Chinese, Islamic, and Indian civilizations.
Alchemy has a notable departure from true sciences in that it focuses very much on mysticism, the occult, or astrology, depending upon its incarnation and practitioner. Spiritualism is common even in the most agnostic alchemists, and the powers revealed through alchemic study are almost always identified as having a supernatural origin. Toying with these powers often comes at great expense to the practitioner, and the benefits of alchemic practices are occasionally outweighed by the danger that they present.
In the Omniverse, the practice of alchemy tends to survive only in universes where magic is present, as the energy required to perform the tasks of alchemy is too great to be performed with typical technology.
A central concept of most alchemical practices is the idea of transmutation; that is, changing one physical element into another. This is most easily identified in the common practice of turning lead into gold. This is a task which requires an enormous amount of energy, not easily obtained without the use of magic or powerful focus similar to that required by those who use chi for their supernatural abilities.
Transmutation can also refer to the process of changing the structure of existing matter; for example, making something more brittle or sturdy, or changing the shape, volume, or density of some piece of matter.
Transmutation of living matter
Alchemy neither creates nor destroys matter, it simply alters its shape or structure. In this way, complex structures such as cells and tissues can be very difficult to assemble. Some alchemists do manage to create an empty shell in the form of a living being, known as a homunculus. Others, either more desperate, more foolhardy, or a mixture of the two, perform transmutation on already living tissue or on recently deceased tissue. Healing is possible, but in order to recoup the lost "life force" of the cells, tissues, or individuals, an equal amount of "life force" is extracted from the practitioner, leaving them near-death or with grievous bodily injury.
Goals of Alchemy
The Elixir of Life
Many alchemists seek to create an Elixir of Life. This mystical concoction is said to act as a cure for all diseases and the ultimate form of medicinal magic.
The Philosopher's Stone
The Philosopher's Stone is a powerful alchemical artifact of legend with several defining properties. Firstly, it aids in the transmutation of elements, easily converting common metals into solid gold. Secondly, it acts as a panacea, with the ability to cure all diseases in conjunction with the Elixir of Life. Finally, it can provide immortality to the bearer, extending their life indefinitely longer than they might otherwise survive. With these three powers used in conjunction with each other, one who achieves the creation of the Philosopher's Stone would be a force to be reckoned with, having near complete power over life and death.