Hi Cassie, ever since I started reading your Shadowhunters books I've loved the world you created and I'm amazed at how you manage to build it out more and more with every book you write. Do you have any tips or tricks regarding worldbuilding? How did you go about creating this amazing world?
I could write a whole book about world-building — in fact, there are lots of books about it! Every book, even contemporary fiction, requires world-building: you are always creating a sense of place, time, and character in a story, which is essentially what world-building is.
Obviously fantasy has specific elements of world-building that other genres don’t have, so that’s what I’ll talk about — briefly — here. These are a few steps you need to consider when you’re building a fantasy world, be it an open world or a closed one.
1) What’s your normal?
You’re always going to establish what the norm is in your world before you do anything else. You don’t have to get into the nitty-gritty, but set your basic ground rules. Is there magic? If so, what’s the cost of magic? (Power is never free — it always costs in effort, knowledge, body parts, etc.) Does everyone know about magic (in which case yours is an open fantasy world)? Is it a secret (closed fantasy world)? What’s your time period? Tech level?* What are the major antagonists of your world? What are the biggest dangers? And finally, what’s the main thing your character wants? That may seem like character work, but it’s intrinsic to world-building. If your character wants above all other things to be King, for instance, then you know you have a monarchy.
*Remember Clarke’s First Law: Any sufficiently advanced technology is indistinguishable from magic. In other words, you can usually have magic or super-advanced technology, but not both, because they do the exact same thing in a story. Location spells are pointless if you have GPS tracking devices implanted in everyone. If you are going to have both, you have to figure out how what they do is different. Otherwise you are giving Spiderman the power of flight, thus rendering his web-slinging useless. So give it thought!
2) Make your rules.
Otherwise known as internal consistency. Our world is governed by natural laws that determine what people can and cannot do. A world you make up must be the same. What if only some people can do magic? Then you have to figure out who they are, why they can do magic, what rules govern the practice of that magic, how the rest of the population feels about them, and what that magic is based on. While you don’t need to — and shouldn’t — explain every detail of these rules on-page, your characters have to abide by them. We need to believe these are real people who are governed by an internally consistent set of strictures that shape and define their behavior. If your main characters live in a walled city that closes at night, show us that by having them worry about getting back before the gates shut.
3) Break your rules.
Half the reason you established your normal is so you can fuck with it. Stories are about conflict. They’re about the moment things go wrong, not about things going right. They’re about things suddenly not conforming to expectations. If you have a land ruled by a benevolent King everyone adores, assassinate him. (Even better if your main character does it.) If you have a world where women can’t do magic, you need a badass sorceress to rise. If parabatai can’t fall in love, make sure two of them do. If Shadowhunters are the descendants of angels, what happens when one is a descendent of demons? Once you build your world, your first question should be, What is this story going to do to change it?
4) Everything hews to a theme.
Think about the thematic implications of your world. If you’re building a low-tech, high-nature faerie world, think about the way not having tech, and having nature magic fill a lot of those uses, will influence the way the characters talk, the expressions they use, what they wear (nothing with zippers, nothing mass-produced) the way they live their day-to-day lives (alas, no flush toilets). For instance, the thematic character of the Shadowhunters books is defined by the overarching mythology of angels and demons. Seraph blades, which have to be activated by speaking an angel’s name, hew to that theme. Everything the Shadowhunter characters do is defined by their belief that they have angel blood (or fear they have demon blood.) Whenever I build new mythology into the Shadowhunter world, I have to think “Does this fit with who the Shadowhunters think they are, their priorities, beliefs and history? Is this something that could or would happen in this complex, small, militaristic society?”
It can help to think of it as an aesthetic, as if you were putting together a house. Does this piece go, or does it clash with everything?
5) Small details.
Little pieces that feel unique and true help build out a world. Rather than spending your time detailing the entire history of the Royal Family for a thousand years, create a room in the palace where the faces of royal enemies are dried, stretched and mounted in glass. Now we know the Royal Family is creepy, which is more interesting than knowing everyone’s grandparents’ names. Stuff that isn’t momentous is fine if it’s interesting. Random stuff I know about Castellane, the city in Sword Catcher: interior light comes from carcel-lamps, dentures are made from the teeth of dead soldiers, the Queen loves kalamansi fruit, and if you fall in the bay, a crocodile will eat you. Think of the big world-building details — names of countries, the type of religion, the way magic works — as the walls, beams, and floors of your house. The small details are your paint, wallpaper and furniture. One is a structure; the other is the sense and character of that structure.
There’s a lot more to say about world-building, and I’m always happy to answer writing questions. It offers me an amazing opportunity to procrastinate. :) Good luck!











