Fantasy is a genre, more than perhaps any other, that embraces incredibly intricate world-building. It’s an essential part of the fantasy story, which by definition includes some element of something other. Whether it’s vampires and wizards in Harry Dresden’s Chicago or the sprawling kingdoms of A Song of Ice and Fire, part of the author’s job is creating a living, breathing world the reader can believe in.

{{The nature of magic, the sine qua non of fantasy, is perhaps the most basic decision the author has to make. What kind of supernatural powers are available and who can use them determines the basic structure of the universe, and from there the nature of the societies that exist in it. Worlds where anyone can learn a few spells are very different places from places where a tiny handful of wizards are worshipped as god-kings; a world where magic is the exclusive provenance of mysterious spirits is utterly unlike one in which it follows well-understood rules and formulae. The possibilities, of course, are endless.

It’s always tempting to dive right in and starting building something grand. Indeed, many fantasy authors I meet got into the genre precisely because they had a magic system they wanted to write about. What if all spells came from consuming fungi? Or what if everyone could transform into birds at the new moon? Or, or, or—and so it goes. There’s nothing wrong with this basic approach, and I’ve gone that route a few times myself, but lately I’ve started asking myself a few basic questions about the kind of story I want to tell before getting started.

Writing a solid, coherent story becomes far easier when the magic system—indeed, the entire world—supports the kind of narrative the author is trying to tell, rather than fighting it. In contrast, when world and story are poorly match, it’s easy to tell; the author must constantly introduce patches and props to keep the nature of the world from ruining the story they’re telling. A magic system that’s full of arbitrary and inexplicable exceptions (we can’t teleport over running water, light spells don’t work more than 40 feet underground) or suspiciously convenient counter-abilities (my amulet protects me from mind-reading) is probably in conflict with its story. Avoiding this trap is not terribly difficult. Before getting down into the weeds of world-building, the author simply needs to answer a question about the basic nature of the story.

What kind of obstacles are my characters, in general terms, going to be facing? We only need to speak in the broadest of generalities here. Is this going to be a story about retrieving some object or person? Crossing vast distances? Defeating powerful enemies? Stories can include any number of things, but think about what the major elements are going to be.

Once you have a vague idea, the trick is to make sure the magic system doesn’t trivialize those obstacles. If an easy solution to a problem is available, but you want it to be hard, then you’ll have to resort to one of the dodges discussed above. This is hardly the worst thing in the world, and nobody can avoid it all the time, but making sure the magic and the story are in harmony from the start can help minimize things.

So if we have a story about traveling a long way under grueling conditions, the magic of the world ought not to include easy teleportation, flight, or other means of bypassing the problems of travel. The world of Robert Jordan’s The Wheel of Time, for example, with its Gates and other long-range magic, would be a poor match for the story of The Lord of the Rings. It’s not that you couldn’t tell a travel story in that world, it’s just not a natural fit, and it would require lots of restrictions and special conditions.

Similarly, if a story is going to be about fighting monsters, the magic system should make the fighting of monsters as interesting as it is possible to be. Brandon Sanderson’s Mistborn has a complicated mix of powers that makes combat between its magical characters intricate and thrilling; it wouldn’t be an ideal place for a story out of A Song of Ice and Fire, with its emphasis on human-scale relationships and limitations.

For my own series, I knew before I started designing the world that I wanted it to involve a lot of military actions and political maneuvering, using the vague historical template of the wars of the early 1800s. That meant, crucially, that the magic couldn’t be ultra-powerful in combat, because it would trivialize the kind of action I wanted at the center of the books. Mistborn‘s magic system, with its emphasis on super-powered individuals, or The Malazan Book of the Fallen‘s world of army-slaughtering demigods, would have meant a great deal of tedious backfilling in order for the musketry and cavalry charges to mean anything.

Keeping that in mind, I designed the magic of The Shadow Campaigns to suit. Characters can be powerful in a personal fight, but not enough to make an enormous difference on the battlefield; magical individuals tend to function as spies, agents, and assassins rather than on the front lines. A little planning ahead saved me a great deal of effort later on, answering questions of the form “Why don’t they just …?”

The idea of planning a world around a story seems, to some people, getting things back to front, and it’s not always the perfect approach. But it’s something to think about, you’re sitting with a blank piece of graph paper, getting ready to sketch out the contours of the world; there’s no need to try to force a square peg into a round hole when you’re the one who gets to design the hole!

Django Wexler is the author of The Shadow Campaigns. Book three in the series, The Price of Valor, was released on July 7.