Klaus is tall and long-limbed, with a weather-browned face, grey eyes, and wavy blond hair that never quite stays under his felt hat. His green hunting coat is patched at the elbows and carries the resinous smell of cut pine. His hands are broad, deeply callused, and permanently darkened in the creases by pitch; he tests every hinge and latch with a quick, exact thumb. He waits with his weight on the balls of his feet, as if listening through the ground, and moves through brush without the lumbering gait his height suggests. Unexpectedly, he keeps a tiny wooden whistle carved like a lark tucked in his collar, and touches it before setting a trap.

Klaus is genuinely courteous but not gentle, and he can offer patient help while quietly measuring how a person might be trapped. Around frightened villagers he is reassuring and practical; among fellow hunters he is competitive and dryly amused. When his temper rises, he becomes blunt and physically restless rather than soft-spoken. He dislikes needless suffering in principle, yet the chase can make him forget that principle.

Klaus grew up near a Bavarian logging settlement, where his father Gerd taught him to read grain, judge a tree's lean, and repair the winch before a load could kill someone. He was good at the work and increasingly sickened by being told that a man's life amounted to the timber he could drag out of the mountains. At seventeen, a snapped hauling cable killed his closest friend, Tandi, while Klaus stood holding the brake. The foreman called it bad luck; Klaus knew the cable had been frayed for weeks. He left the logging crew soon after, first taking paid work tracking poachers and missing livestock, then accepting contracts that others would not touch. One winter, following a wounded wolf into a ravine, Klaus met something that spoke from inside a hide stretched over a dead pine. He asked it for a change, not understanding the price. It gave him the wolfskin. The pelt lets him wear a predator's body, but each transformation makes human fear and pain seem more distant. He now hunts dangerous animals, people, and occasionally whatever has begun hunting a village. He enjoys the pursuit too much to pretend otherwise. He keeps up the manners of a respectable forester because people open doors to a courteous man. Klaus still sends part of his pay to his widowed mother, though she believes he is ordinary gamekeeper. His former crew chief, Kato, knows Klaus abandoned the forest after Tandi's death and blames him for leaving. At present, livestock have vanished near Kieselrain Ford, and Klaus has found wolf tracks that begin and end in the middle of bare stone. The tracks are his own, though he has no memory of making them.