I have a passionate love for books with magic or superpowered people and I’m currently in the processing of writing my own little fantasy tale and, let me tell you, as fun as imagining a make-believe world is, it’s insanely difficult to establish a coherent magic system. Depending on the kind of story you’re writing, a magic/power system can be as comprehensive or as mysterious as you want and oftentimes even just deciding which route to take can be difficult.
In my opinion, a story can have the most fascinating magic/power system ever but if that system doesn’t have consistent rules, if the system can’t even stand under basic scrutiny, then the whole story will flop. Willing suspension of disbelief can only go so far and when you’re dealing with magical folk you’re treading on thin ice to begin with. Now, from what I’ve gleaned from weeks of on-and-off research, making a rational magic/power system is attainable if you take three things into consideration: the verisimilitude of the system, the conflict/s that the system invokes, and the impact of the magic/power to users, non-users, and society as a whole.
As an example, let’s take a look at Marissa Meyer’s triumphant sci-fi adventure series, The Lunar Chronicles. Although the book series doesn’t have as extensive a magic/power system as in a Tolkien tale or any Tamora Pierce book, I believe The Lunar Chronicles is a great example of how a simple superhuman ability can shape a simple story into a complicated, riveting yarn.