Brandon Sanderson Provides Update on Mistborn Screenplay Progress

The acclaimed author says he's 10% done with the screenplay adaptation of his Cosmere universe for Apple TV.

Published on Feb. 19, 2026

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Brandon Sanderson, the bestselling author of the Cosmere fantasy book series, has provided an update on the progress of the Mistborn screenplay he is working on for an upcoming Apple TV adaptation. In a recent YouTube video, Sanderson revealed that he is already 10% done with the screenplay, a significant jump from the 2% he reported just two weeks prior. Sanderson also addressed the cancellation of a planned livestream following the initial announcement of the Cosmere adaptations, citing potential issues with the Writers Guild of America.

Why it matters

Sanderson's Cosmere books, including the Mistborn series, have a devoted global fanbase, so the news of these adaptations has generated significant excitement. However, there were concerns that the screenplay work could impact Sanderson's ability to deliver new Cosmere novels. This update helps allay those fears, showing that Sanderson is making steady progress on the screenplay while still maintaining his prolific book writing pace.

The details

In his YouTube video, Sanderson explained that a minor shoulder surgery had caused him to miss his usual weekly update the previous week. However, he noted that the surgery has not slowed down his work on the Mistborn screenplay, which he says is now 10% complete. This represents significant progress from the 2% he had reported just two weeks earlier. Sanderson also addressed the cancellation of a planned livestream following the initial announcement of the Cosmere adaptations, citing potential issues with the Writers Guild of America. He clarified that he is not yet a member of the WGA, but said he would not write the screenplay if the WGA were on strike, out of solidarity.

  • Sanderson provided the update on the Mistborn screenplay progress in a YouTube video on February 17, 2026.
  • Two weeks prior, on February 3, 2026, Sanderson had reported the screenplay was only 2% complete.

The players

Brandon Sanderson

A bestselling American author known for his epic fantasy book series, including the Cosmere universe which contains the Mistborn series. He is currently adapting his Cosmere works for an upcoming Apple TV series.

Writers Guild of America

A labor union that represents film, television, and digital media writers in the United States. Sanderson mentioned potential issues with the WGA as a reason for cancelling a planned livestream about the Cosmere adaptations.

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What they’re saying

“I bet you're waiting to hear how the Mistborn screenplay is going, and it is at 10%. So, I have made very good progress.”

— Brandon Sanderson, Author (YouTube)

“I got up that day for the livestream and got texts from the publishing team that said there's like a WGA or something and I'm like, 'Okay, let's not talk about me in Hollywood working on a screenplay'.”

— Brandon Sanderson, Author (YouTube)

What’s next

Sanderson plans to do another livestream at some point in the future to provide more updates on the Cosmere adaptations, though he did not specify a date.

The takeaway

Sanderson's rapid progress on the Mistborn screenplay, going from 2% to 10% complete in just two weeks, should reassure fans that the Cosmere adaptations are moving forward without significantly impacting his ability to deliver new novels in the book series. His commitment to avoiding any potential conflicts with the Writers Guild of America also demonstrates his dedication to maintaining creative integrity throughout the adaptation process.