Mages with Muskets: A Conversation with Brian McClellan

Brian McClellan is the acclaimed author of the Powder Mage series and the Glass Immortals series. Both are highly original, adventurous, and inventive takes on the epic fantasy genre, three traits we’re all fans of here. If you haven’t read McClellan’s work yet, don’t worry—this article avoids any major spoilers, though we do discuss the development of his magic systems.

I’m thrilled to have had the chance to sit down with Brian to discuss his process, inspirations, and advice for aspiring writers. 

Your book Promise of Blood has such a memorable title. I heard your editor wasn’t initially a fan—how did it come to stick?

When I first told my editor that title, she goes, “I don’t really like it; we’ll change it somewhere along the way.” And then it never got changed.

Your magic systems and world-building are often praised as being very detailed and immersive. Could you share your process for developing a unique magic system from scratch?

It’s kind of happened in several different ways. Some people have a serious system; they develop these things. With me, I tend to start with a world and just start building something in my head. If the magic pops up along the way, great. Or if I’ve had the world kind of pre-built, then I think of a magic system that slots into that world.

For In the Shadow of Lightning and the Glass Immortals series, that was very much a world I spent years thinking about. There are two connected magic systems: one where magic is made and produced in glassworks, and people wear these little baubles that enhance their bodies. I knew I wanted magic that really had its teeth in the economy. Then, glass dancers—people who can do a kind of telekinesis with glass—came in at the very end of development. I had a totally different magic system I loved but couldn’t make work on the page.

That’s fascinating, and now I’m curious! Could you share more about the original system you had for In the Shadow of Lightning?

I called them clay makers. The idea was that there were mages who could project a force field around them, allowing them to move through solid matter. They could also manipulate solid matter, like picking up a stick and shaping it into something else. But it was too vague and almost too visual. In my head, it worked great. On the page, it didn’t work. 

Speaking of original systems, how do you know when a magic system isn’t working?

Usually, it’s that it’s just not flowing—it just gets blocked. I have this problem where I’ll throw things at the wall. If I really like an idea, I’ll smack my head against it for months, even if I know from the beginning it doesn’t work. Eventually, I have to take a step back, clear the palate in my head, and admit it’s not working. Once I do that, the ideas flood in.

Your integration of gunpowder and firearms into your magic systems is so unique. What inspired this feature?

I was a young author trying to figure out something different. I saw the movie Public Enemies, and immediately thought, “I want to write a short story with mages robbing banks with tommy guns.” Then I watched Sharpe’s Rifles, a Napoleonic War TV show with Sean Bean. Halfway through the first episode, I thought, “No, I need mages with muskets in a Napoleonic setting.” It all made sense—taking a magical world with a traditional epic fantasy vibe and progressing it into an industrial revolution with political upheaval.

Many aspiring writers struggle to make their magic systems feel real and consistent. What advice would you offer?

Consistency is a huge part of it. Hard magic systems—with firm rules—are easier narratively because they don’t constantly create plot holes. Firm rules can feel restrictive as a writer, but they create conflict and structure that help your storytelling. Early on, I sometimes prioritized “rule of cool” over consistency. Looking back, I wouldn’t do that now.

I’ve asked a few of our guests on The Cognitive Realm this next question, and I’m curious what your thoughts are on it. Writer’s block is something every writer encounters differently. Could you share your experience with it?

Writer’s block is a catchall term for struggling to finish a story. I wrote six Powder Mage books without a problem. Then, during the pandemic, a couple of big life events hit me. Something in my brain shifted, and I wasn’t able to write the way I had before. The alchemy of creating a finished book got lost. For the last two years, I’ve been relearning what used to come naturally—diagnosing what isn’t working and figuring out how to fix it. It’s been frustrating but also maturing as a writer.

I think that’s an important thing for young writers to see and know that setbacks are a normal part of the creative process. I love using the term “alchemy” in this context—especially since it implies that, in this process, you’re turning lead to gold. 

Finally, what piece of advice would you leave for aspiring writers?

Don’t take yourself too seriously.

Hear! Hear! Couldn’t have said it better myself.