The Steel Inquisitors are the Lord Ruler's most feared enforcers - terrifying figures with steel spikes driven through their eyes who serve as the religious police of the Steel Ministry. Created through Hemalurgy, each Inquisitor carries numerous spikes that grant them a devastating array of stolen Allomantic and Feruchemical abilities, making them nearly impossible to kill and overwhelmingly powerful in combat. They answer directly to the Lord Ruler and operate with absolute authority, hunting down skaa Mistings, rooting out rebellion, and enforcing orthodoxy within the obligator bureaucracy. Their eyeless faces and relentless pursuit make them objects of terror across the Final Empire. Despite their apparent loyalty, the Inquisitors harbour their own internal politics and ambitions - and their true nature and origins are more complex than even most of the nobility understand.

Kelsier's crew is a team of skilled Allomancers and specialists assembled by the Mistborn thief Kelsier to execute the most ambitious heist in the history of the Final Empire - the overthrow of the Lord Ruler himself. Each member brings a unique Allomantic ability or expertise: Breeze is a Soother who manipulates emotions, Ham is a Pewterarm with immense physical strength, Clubs is a Smoker who hides Allomantic signatures, Dockson handles logistics and finances, and Spook is a Tineye with supernaturally enhanced senses. OreSeur, a kandra bound by Contract, rounds out the team as a shapeshifting spy. The crew is also where Vin - the half-skaa street urchin Kelsier picks up out of the underworld - finds her place. What begins as an elaborate con grows into something much larger, and the crew's bonds of loyalty and friendship are tested as the plan spirals beyond what any of them originally imagined.

The underground resistance movement fighting against the Lord Ruler's thousand-year reign over the Final Empire. The skaa - the oppressed lower class, kept in near-slavery by the nobility - have attempted uprisings before, but all have been crushed with overwhelming force. The rebellion operates in secret cells across the empire, coordinated by leaders like Yeden, who serves as its figurehead during the events of The Final Empire. Kelsier's arrival promises something the skaa have never had: an Allomantic crew, a real plan, and a leader who carries the kind of legend that can move people who have never been allowed to hope.