Nobius looks as if he has spent years listening to weather through walls. His gaze goes first to thresholds, rafters, and the spaces beneath furniture, then returns to a speaker as though he has carefully decided they are worth hearing. His dark hair is tied back with grass cord, but short curls escape around his ears. His cloak smells faintly of rain-soaked bark and carries burrs in its seams. He moves with a slow, testing roll of the feet, like someone crossing a bog without wanting to disturb what lies below. Unexpectedly, he keeps a neat collection of tiny carved wooden birds in his pockets, and will set them in a row while discussing a battlefield.

Nobius is patient with frightened people and impatient with confident plans that have not been tested. He is gentle about pain but unsparing about responsibility. When relaxed, he can be dryly funny and surprisingly fond of small crafts; under pressure, he becomes terse and starts asking for exact measurements. He wants to trust others, yet keeps trying to control the risks they take.

Nobius grew up maintaining flood markers and sluice gates in the low farms around a settlement called Ninth Measure, named for an old military survey mark. His mother, Salla, taught him which reeds signaled clean water; his father, Oskari, taught him to repair a gate before blaming the river. As a young man, he apprenticed to a traveling druid who taught him that a marsh is not empty land but a crowded neighborhood with slow inhabitants. The event that changed him came during a spring flood. Nobius persuaded the village council to open an old spillway, believing it would save the farms. The water instead tore through a hidden nesting ground and drowned a clutch of rare marsh drakes. He spent three days pulling eggshells from the mud. Since then, he studies consequences as carefully as signs, and refuses to call any decision harmless merely because it is traditional. He now serves as a healer, guide, and weather-wise mediator between Ninth Measure's farmers and the wetlands. His closest friend is Salla, a practical ferryman who thinks his caution has become a second religion. A young apprentice, Tavi, keeps leaving town to investigate the ruined spillway, which Nobius has forbidden her to enter. The council wants him to bless a new drainage project, but the marsh has begun drying in patches that should be wet. Nobius suspects someone has been diverting water upstream, and every day he delays confronting the council gives the damage time to spread.