Hand of the Automaton
How Magic Works
Magic particles exist in nature, everywhere, in small quantities. Perhaps they are also created and destroyed in small quantities by plants and other living creatures or something, the key point is that they only exist in very small concentrations.
Magic users pull the particles from all around them and concentrate them into a much denser form, creating spells. These spells then burn off magic particles as they do their thing, the particles power the spell’s effect, but all particles are not used up in the process, and what is left is in a far more concentrated form than found in nature.
This leads to magical residue and fallout, especially from extremely powerful or very sloppily cast spells (which incompetent or inexperienced mages often end up casting). High concentrations of magic particles left over as residue cause all kinds of chaos, which is why the fallout from the war can be so dangerous.
It is worth noting that powerful concentrations of magic particles can be found naturally, even without a wizard’s tampering, and they lead to the creation of natural, stable places of power that men sometimes find and worship or otherwise make use of. Such natural deposits of concentrated magic are very rare, however, and generally quite stable unless tampered with, since they have accumulated over the course of centuries or even millennia.