alchemy.
In the dictionary it's defined as, 'the process of the transmutation of one base material into another'.
It's main rule is that of Equivalent Exchange.
A win-win for both sides, supposedly. You give something for something that you want.
Like pieces of broken pottery for a vase.
Or perhaps a metal lamp for a sword.
Or maybe, just maybe…a leg and and a body for a monster.
An arm for a soul.
The Philosopher's Stone for a chance to live a normal life again.
The reality of alchemy is that it is nothing but the devil's magic.