Ostresh looks like the sort of handsome man who has already guessed which person in the room is lying. His auburn hair is thick and carefully brushed back, with copper glints where lamplight catches its slight wave. A neat, sharply waxed moustache frames a quick, lopsided smile. He moves with a fencer's economical balance, never quite standing where an opponent expects him to be. His clothes smell distinctly of bergamot, beeswax, and the faint smoky tang of a recently extinguished cigar; he knows about the scent and claims the cigar is for other people's benefit. In a room, he leaves an impression of polish with a small, deliberate mismatch beneath it: a man dressed for a portrait who is already planning the quickest exit.

Ostresh is warm and generous when someone is frightened, but can be maddeningly evasive when someone asks what he himself needs. In a crowded salon he is theatrical, quick with flattery, and alert to every exit; in a private room with a grieving person he becomes plainspoken and patient. He admires courage but distrusts grand gestures, and he likes being liked more than he likes admitting.

Ostresh Sokolov grew up in a rented attic above a shuttered bell foundry in the river district of Sumpford, a place locals still call Bell-and-Bucket after the foundry merged with a water-hauling concern no one wanted. His father, Mikhail, repaired clocks and lied about the price of every repair; his mother, Varka, kept a boardinghouse and could identify a guest by the sound of their boots on the stairs. Ostresh learned to read hands, doors, and debts before he learned to fence. At twenty, he was hired as a courier by the Harrow-and-Herring Exchange, a respectable-sounding shipping concern named for two businesses forced together after a dockside fire. He discovered that its directors were selling the names of dissidents to a royal jailer. During a winter transfer, he stole the list and freed twelve prisoners, but the escape went wrong: a young guard named Bram was killed in the confusion. That night changed him. He stopped treating cleverness as a substitute for choosing a side, though he still tries to make every choice look like a joke. Years later, he became an indispensable fixer among Sumpford's theaters, countinghouses, and noble salons. He remains close to his mother, who is now too proud to ask for help, and to his former partner, Sigrid, a practical locksmith who refuses to forgive his habit of making decisions for her. His current problem is that someone has begun sending him exact copies of the prison list he thought he destroyed, each with one name newly crossed out.