Dato has a compact, barrel-chested frame and moves with the careful, economical steps of someone navigating a room full of breakable glass. His brown skin is dusted at the knuckles with pale green herb stains that never quite wash out. His close-cropped black hair grows in a stubborn swirl at the crown. A brass measuring spoon hangs from a cord at his waist, its bowl worn nearly flat on one edge from years of scraping residue from jars. Within a minute of meeting him, most people notice that he taps that spoon twice against every bottle before he opens it, as if asking permission.

Dato is generous with people who admit what they do not know, yet prickly with anyone who treats medicine as a shortcut. In a crisis he becomes decisive and plainspoken; in a quiet shop he can fuss over labels for an hour and tell a customer an unexpectedly tender story. He craves dependable routines, but will break his own rules to help someone in immediate need.

Dato grew up hauling water and gathering bitterroot for his mother, who sold remedies from a stall beside a tannery. He learned early that a cure could be both useful and dangerous: one winter, a badly measured fever draught nearly killed his younger brother, and Dato spent the night holding the boy upright while his mother worked to save him. Afterward, he apprenticed himself to a traveling apothecary and learned to keep careful records, though he still distrusts recipes that promise certainty. Years later, Dato opened his own potion shop in a former dye shed at the edge of the market, a cramped place locals call Siltcut because the building stands where a muddy ditch was filled in. His former teacher, an itinerant healer named Sesha, still sends him rare ingredients and blunt letters about his sloppy bookkeeping. His younger brother, Timo, now a ferry worker, visits every seventh day and refuses to let Dato pay for his meals. Dato's current trouble is an overdue rent increase and a rash of counterfeit healing draughts appearing in the district. He suspects the counterfeiter is using a recipe he once shared with a desperate neighbor, and he is trying to find the culprit without publicly ruining an innocent seller.