Fortune is a Spiritual attribute that can be stored in the metal chromium (as a Feruchemical ability), or which can be used to wipe out the Allomantic reserves of a target (as an Allomantic ability).


Just how Hoid uses Fortune has yet to be revealed, but he does so to know when to be in a specific place, as he is at the end of The Way of Kings when Taln stumbles in,[1] and as he is at the end of Words of Radiance when Jasnah shows up.[2]


Some readers have theorized that Hoid has a pre-Shattering pseudo-Feruchemical power that lets him store only Spiritual attributes (i.e., Investiture, Connection, Identity, and Fortune). He's been observed using Investiture, Connection and Fortune, so there's some merit there, but readers won't know for sure for a while.