A petite young woman stands with her shoulders tucked close, poised lightly on the balls of her feet as if every rooftop were a path she might need to take. Rain beads on her jaw-length dark curls and glistens along the neat seams of her clothes. Her olive cheeks flush pink in the cold; amber flecks in her hazel eyes catch the lamplight above a quick, guarded half-smile. Her palms and fingertips are faintly roughened by years of hauling wet lines and testing stonework, and she unconsciously rubs one thumb along the edge of her cuff. She leaves the impression of someone already planning three exits, though she is trying to make you feel welcome.

Sella is alert and capable when a practical problem needs solving, yet awkward when someone offers her care. She can be brisk with strangers and teasing with friends; under pressure her humor turns dry and her attention narrows to exits and hazards. She wants to believe people can be trusted, but has learned to check their promises against what they actually do.

Sella grew up above a rain gutter maker's shop, learning the old city's rooflines by carrying messages between workers and watching where water gathered after storms. At sixteen, a cloudburst flooded the cramped rooms beneath the street where her younger brother Tavi was sleeping. Sella found a blocked drain and cleared it by hand while the water rose around her; Tavi survived, but the delay and the city's neglected channels left their mother with a lasting illness. Since then, Sella has mapped the drains and quietly warned tenants when the rain turns dangerous. She keeps up a prickly friendship with the rooftop gardener Ilyse, who provides shelter and argues that Sella cannot rescue everyone alone. Her current trouble is that a wealthy property holder is sealing public runoff passages to protect a new courtyard, pushing floodwater toward the poorest stairwell in the district.