The Deus Ex Machina Problem: Sanderson’s Mistborn Adaptation
Speculation on how Sanderson will change the ending of Mistborn book 1 for the film adaptation
I was thrilled to hear this week that Brandon Sanderson has finally sold the rights to his Cosmere novels. Amazingly, he retained creative control of the project, and he’ll even be writing the screenplay for the first feature film adaptation of book 1 of the Mistborn series, Mistborn: The Final Empire. The part I’m most excited about is seeing how Sanderson will rewrite the ending. Sanderson has long been saying that in retrospect, he wasn’t happy with the original ending. And now he’s finally gotten his opportunity to do. Before we continue, this post will contain spoilers for the ending of Mistborn book 1. If you plan to read it, then I strongly recommend you stop reading. You’ve been warned!
How did Sanderson, an author known for the satisfying midpoint and ending twists in his novels, write an ending he wasn’t completely satisfied with? What happened is he had already started working on the outline for the sequel. Elements from book 2 started bleeding into book 1, without being properly motivated in book 1.
The problem with the ending is a bit of Deus ex machina moment. For the uninitiated, Deus ex machina (God from the machine) refers to a moment where there is a sudden and unexpected solution to a difficult problem. In the novel, the main character Vin in her ultimate confrontation with the Lord Ruler, the Big Bad, when she discovers a hidden power. She can inhale the mist and use all the metals simultaneously. While researching this article, I realized that this ability is subtly foreshadowed. Specifically, when Kelsier theorizes the possibility of Allomancers burning metals, they shouldn’t be able to. In fact, her hidden power is internally consistent with the magic system. As a “Mistborn”, Vin has access to all the metals. Much of the book is her training in how to use each metal. So it logically follows that a Mistborn could use all the metals at once.
The issue is that it feels random. In his 2025 lecture, Sanderson says a good ending is surprising, yet inevitable. Inevitable in the sense that it has a strong causality with the previous events. A great ending encourages the reader to revaluate everything they’ve learned up to that point. Even if a character’s hidden ability is well motivated by the magic system, it can’t feel like it came out of nowhere. Ideally, the reader will figure it out right before it’s revealed. And it should be possible for a reader to figure it out sooner if they’re reading very carefully.
As fans of speculative fiction, let’s do a little speculation on what might change. Let’s start with the obvious options. He could plant more seeds along the way about the power. Or he could lean into the spectacle of the visual medium and make the power unveil be a moment of wonder powered by CG. For some reason, I think he’ll restructure the story completely.
Since this is fantasy, there’s always the power of friendship ending. Sanderson set out with the intention of writing an ensemble novel about a heist. It ended up being more of a master-apprentice novel focused on Vin’s relationships and power scaling. If the film has A-list actors attached as members of the crew, we’d expect them to have bigger parts.
Another possibility is that burning all the metals has a higher power cost, forcing Vin to make more of a sacrifice. This could elegantly explain why Vin becomes an assassin for the new empire. Not as a choice, but as a consequence of what she had to do to save it. In a way, she is becoming the thing she fought to defeat. It’s all a bit too tragic though. Sanderson’s writing strives skews towards the optimistic. It also somewhat undermines the romance subplot, diluting the stand up and cheer moment when Vin is reunited with Elend.
Whatever Sanderson does, the film gives him something most authors never get: a chance to fix what bothered him. And given his track record, I’m sure it’ll be great.