Thaddeus Dusk is a wealthy merchant who provides a number of goods to the upper class of Brightstone. He’s also extremely well connected in the Night Market and has a number of contracts for things going into and out of the city.
His daughter, Leah Dusk, was almost abducted by Ulf Ironborn’s gang. They were hired by agents inside of the Skovlan Embassy to kidnap her and use her as leverage to get Dusk to do their bidding (acquire weapons, and otherwise help assist a second rebellion). This plot was foiled by the Night Crows after Irimina tipped them off to the problem.
Mechanically, Dusk acts as the Crew’s upper-class fixer.