Book 3.5 in the Mistborn series (2016)
Publisher: Tor Books
Mistborn: Secret History is a companion story to the original Mistborn trilogy.
Building upon the characterization, events, and worldbuilding of the original trilogy, this novella offers a rare glimpse behind the scenes at the fate of a certain reader-favorite character.
Ten years in the making, Mistborn: Secret History might answer a few of your questions.