Yori is a wiry child with a surprisingly broad jaw and small, square teeth that show whenever they grin. Their short, springy steps seem to place them on the edges of their boots; while waiting, they lean forward with their weight over their toes, as if the floor might suddenly become a riverbank. Their skin has a warm brown tone, their hair forms tight black coils usually mashed flat beneath a cap, and their dark eyes keep flicking toward exits and rooftops. They leave the impression of a sparrow that has learned exactly how far a cat can jump. Unexpectedly for a rooftop runner, they carry a little bundle of dried herbs and know how to soothe frightened animals.

Yori is quick to laugh and quicker to notice who is being ignored. They can be bold when protecting someone else, yet dodge questions about their own feelings with jokes and errands. On a calm day, they patiently tend animals and teach younger children safe routes; under pressure, they become clipped, watchful, and prone to deciding that only they can solve the problem.

Yori grew up in the flood-prone lower quarter of Kestrel Ford, running messages between roof gardens and ferry landings for their aunt, Tika. They learned the alleys by smell: wet rope, yeast, fish scales, and the bitter smoke from the dye works. At eight, a storm broke the old river barrier. Yori was sent to fetch help, but froze when they heard people trapped below a collapsing footbridge. Their friend Garen went back without them and suffered a crushed leg. Yori still carries the guilt, and the two now argue whenever Garen insists on taking risks. Since then, Yori has trained to move quickly and notice danger early. They secretly pass warnings to the residents before the district's landlords send enforcers to clear them out. Now the landlords plan to demolish the riverside homes, and Tika has vanished after discovering a map showing that the flood barrier was deliberately weakened.