Gen 6 starters ladies and gents!
All authors eventually have this moment, mine later than some because I've tried my damnedest to ignore it, and that is the regret of your first try.
So about 2 hours ago I sat down and read straight through my one good story (and that in itself is a stretch) "Mystery of the Forest". A history based fanfiction where I tried to tell the backstory of equestria and than half-way through writing tried to tie it into being the history of another big fanfiction at the time "Living the Dream".
Magik is the energy of which the Equestrian planet and/or universe thrives upon. It permeates all that can be seen and is the basis behind all forms of existence, living or otherwise. The Everfree is the only place shown where magik is not in play in the greater scheme of things but is otherwise a "null zone".
Magik has been shown in show and discussed via the creators to some extent but is left otherwise to fan speculation. what we know out right is this.