Tesh has warm umber skin with a fine dusting of pale freckles over the bridge of her nose, and close-cropped hair that grows in tight, springy coils. A faint line of tiny brass rings runs along the outer edge of one ear, each ring stamped with a different canal toll mark. She moves with a sideways, tide-watching gait, always favoring her left foot as if testing the floor for hidden water. Her hands are broad, ridged with rope calluses, and stained blue-black at the nail beds from years of handling river dye. She is a canal runner and cutpurse who habitually carries a child-sized wooden spinning top, which she turns in her palm while listening. Her presence leaves the impression of someone already mapping every exit, but not yet deciding whether to use one.

Tesh is quick to laugh when danger is distant and brutally practical when it arrives. She enjoys the cleverness of a clean theft, yet refuses to treat people as pieces in a game. Around strangers she is brisk and teasing; with workers she trusts, she becomes patient and generous. When ashamed, she turns evasive and tries to solve the problem alone.

Tesh grew up among the workers who kept the sluice gates and dye channels of Siltmarket running. Her mother, Nima, taught her to read current by the sound against a wall; her older brother, Paku, taught her that a fast hand could feed a family when a foreman withheld wages. At seventeen, Tesh was carrying a message through a flood tunnel when a gate failed. She could escape alone or turn back to free a trapped work crew. She went back, and the delay cost her brother his life. The survivors remember her as the one who saved them; Tesh remembers the choice as a debt she cannot settle. She now runs messages, recovers stolen goods, and quietly redirects food and medicine toward canal laborers. Her former employer, Jori, still claims she stole a sealed packet that could ruin several officials. Tesh is trying to find the packet's intended recipient before Jori does, while her mother urges her to stop picking fights with people who own the gates.