Cethrin looks like a compact, carefully assembled man of weathered walnut skin, with a broad nose, a neatly trimmed white beard, and brows so pale they seem dusted with mica. He stands with his weight pitched forward over the balls of his feet, as if testing the floor for a hidden seam. In a crowded room he takes up less space than his bright, many-faceted coat suggests: he turns sideways to pass, and angles his shoulders toward whoever is speaking as though giving them the whole room. When thinking, he studies people in reflections rather than looking at them directly. The unexpected detail is his soft, almost absurd fondness for plush toys; a faded felt duck is tucked into the inner pocket of his archmage's coat.

Cethrin is generous with knowledge but guarded with blame: he will spend an hour teaching a novice to set a stone, yet evade a direct question about his own failures. In a calm workshop he is playful and indulgent, letting apprentices argue over tiny details; under pressure he becomes brisk, exacting, and unwilling to delegate. He wants to be trusted, but keeps secrets in the name of protecting others, which makes him difficult to trust.

Cethrin grew up among the lapidaries of Serev, where his mother, Delya, taught him to read a stone by touch before he could reliably read a book. At nineteen, he apprenticed to a court enchanter and discovered that a flaw in a gem could carry a spell farther than a flawless stone. His first celebrated work, a set of protective crystal buttons for a flood-prone village, saved dozens when the river broke its banks. His reputation grew, and so did the demands placed on him. Years later, during the Siege of Veyr, Cethrin built a network of enchanted beacons to guide refugees through smoke and rubble. One beacon was stolen and altered by his former apprentice, Pell, who redirected it to illuminate the besiegers' artillery. Cethrin's own design helped bring down a refuge hall. He has never told the public the whole story. He still corresponds with Pell's sister, Maura, who sends him news of the fugitive and refuses to forgive him for abandoning the search. Now Cethrin's most ambitious commission, a portable ward meant to protect an entire district, is failing in tests. The stones are singing out of tune, and he suspects someone has been quietly replacing them.