Mistborn TTRPG: Brotherwise Bridges the Golden Era and the Future of the Cosmere

Brotherwise Games is taking an ambitious step by releasing a trilogy of Mistborn books for the Cosmere RPG system, expanding Brandon Sanderson's universe far beyond The Stormlight Archive, which had been adapted earlier. This launch is not merely a game supplement but a bridge between two eras of story on the planet Scadrial and a foundation for the next trilogy, which has yet to be written.

The three books—Mistborn Handbook, Mistborn World Guide, and the Mistborn Legacy campaign—cover Era One and Era Two, the two periods Sanderson has explored in the novels. But according to Meric Moir, co-lead designer of the World Guide, the creative process at one point reached a critical juncture. Sanderson, who was working on the Era Three novels, worried that game content would constrain his room to maneuver. “There was a moment about a third of the way through development where we might only have been able to work on Era One,” Moir said in a virtual interview with Polygon. “Brandon was very careful that we didn't box in his ideas.”

Intensive negotiations with Dragonsteel Books eventually produced a compromise: Brotherwise was given latitude to explore Era Two—set in a period resembling the Gilded Age—as long as it did not touch the main plot of the upcoming trilogy that will take Scadrial to an equivalent of the 1980s. The team also added lore about how an entity such as the god named Autonomy first became aware of Scadrial and formed a secret organization called the Set. “They started giving us the freedom to propose ideas, and then Brandon would review them and say, ‘I hadn't thought of that, go ahead,’ or ‘I don't have plans there, try developing it,’” Moir said.

Canon consistency is strictly maintained. Johnny O'Neal, co-owner and creative director of Brotherwise, holds weekly meetings with Dragonsteel to scrutinize every visual element. This effort is crucial because the Mistborn World Guide is the first appearance of a number of characters who will appear in the Apple TV adaptation. Moir hopes that some details that have been locked in—such as Dockson's ethnicity being established as Black and Shan Elariel being of mixed heritage—can carry over to the screen. “I don't know what Dragonsteel or Apple will decide later, but I hope what Brandon has already canonized with us can be translated into live-action,” he said.

Mechanically, the Mistborn TTRPG offers striking complexity. Users of the metal gold, for example, have only two talents for seeing alternate versions of themselves, while iron, which pulls metal objects, has seven talents. “Brandon and his team said, ‘Sorry, Brotherwise, fans don't know everything gold can do. There will be more, but we can't reveal it yet,’” Moir said. “We can only discuss what is known now, and that is still little. Fortunately, our system allows talents to be added later.”

Equally interesting, the game rules also imply the potential for worldhopping—travel between planets in the Cosmere. Burning aluminum seems useless on Scadrial, but an illustration in the book shows someone using it to neutralize the power of a surgebinder from Roshar. Moir revealed that playtesting tested not only balance between metals but also the interface with the Stormlight book and the magic from Warbreaker and Elantris. “Worldhopping is the thing Cosmere fans always ask about in the first or second sentence. Supporting it more solidly going forward is clearly on our radar,” he said.

Moir also serves as RPG director for Plotweaver, Brotherwise's core rules system. He designed those rules with a long-term vision, including the possibility of applying them in the Cosmere. “Take the vehicle rules. We're working on a science fiction setting with spaceships, but the core rules are modular. We can pull them back into the Cosmere when the story reaches the Space Age and adjust them to Brandon's needs for the Isles of the Emberdark story,” he explained.

With this launch, Brotherwise is not merely selling game books but building an ecosystem that can grow alongside Sanderson's work. Fans in Indonesia who have followed the Mistborn and Stormlight Archive novels now have a chance to explore that world interactively, although the physical books are still imported. The next project will be announced at Dragonsteel Nexus this December. Will the Cosmere's space age become a new chapter for tabletop role-playing games, or will it open the door to a broader screen adaptation?