Shadows of Self: A Mistborn Novel (The Mistborn Saga, 5) book by Brandon Sanderson

Waxillium Ladrian was a lawman in Scadrial''s ungoverned frontier region, known as the Roughs, where he worked with his eccentric but effective buddy, Wayne. They are "twinborn," meaning they are able to use both Allomantic and Feruchemical magic. In their world, technology and magic mix, democracy contends with corruption, and religion becomes a growing cultural force, with four faiths competing for converts.

This bustling, optimistic, but still shaky society now faces its first instance of terrorism, crimes intended to stir up strife. Wax and Wayne, assisted by the brilliant Marasi, must unravel the conspiracy before it stops Scadrial''s progress in its tracks.