Mistborn: Secret History is a fantasy novella by American author Brandon Sanderson, written as a companion story to the original trilogy of the Mistborn series. It was published as an ebook-only novella by Dragonsteel Entertainment LLC, a company owned by the author, on 30 January 2016. The novella follows the story of Kelsier from the time of his death in The Final Empire and concluding with the events of the last book in the original trilogy, The Hero of Ages.