Yun is a compact, broad dwarf with the dense, squared-off build of someone used to bracing against a load. He waits with his weight pitched forward onto the balls of his feet, as if a heavy door might need stopping at any moment. He takes up less space than his shoulders suggest, turning sideways through a crowd without seeming to notice he has made room for everyone else. His beard is braided into two short, stiff forks that tap his breastplate when he walks. The unexpected detail: he carries a tiny, carefully maintained folding paper fan, which he opens to cool his tea and never uses to fan himself.

Yun is cautious about structures and reckless about putting his own body between danger and someone else. He makes room for a stranger in a crowded shelter, then argues fiercely over who is responsible for the missing supplies. When relaxed, he is quietly funny and enjoys fussy tea rituals; when anxious, he turns every conversation into a checklist. He wants to be trusted, but finds it difficult to ask for trust directly.

Yun was raised among the stonecutters of Third Kiln, a settlement named for the trade that built it. His mother, Deki, taught him to judge a wall by the sound of a tapped chisel; his younger brother, Rusk, wanted nothing to do with stone and left to work the river barges. Yun became a road-and-bridge warden after a spring flood swept away a loaded cart and its driver. He had heard the bridge groan beforehand and dismissed it as ordinary settling. The driver was his first mentor, and Yun has never forgiven himself for not closing the crossing. Years later, he organized the evacuation of Third Kiln when a retaining wall cracked, saving dozens but leaving the old stonecutters' quarter to collapse. Now he guards the rebuilt pass, where timber merchants keep trying to reopen an unsafe branch road. He is in quiet disagreement with Kiro, the district assessor, who wants to keep the road closed, and with Tada, his brother's partner, who needs it open to earn a living.