Klaus is a lean young man with a wolfish stillness that makes his ordinary clothes seem like a disguise. His blond hair falls in unruly waves, but he combs it back with careful regularity and keeps the sides trimmed with a small knife. His grey eyes rarely settle on a speaker's face: they check hands, doorways, and the dark beneath windows, then return as if he had never looked away. He moves lightly on the balls of his feet, with a measured, economical gait. People remember the odd contrast of his precise grooming and his habit of letting a wet dog shake itself dry against his coat without complaint.

Klaus is proud of his endurance but uncomfortable with praise, and he can be stern about boundaries while unexpectedly generous when someone is cold, injured, or stranded. Around strangers he is watchful and sparing with trust; around people he has accepted, he is wry, practical, and stubbornly dependable. Anger makes him more direct and more willing to act, not quieter or gentler. He dislikes being treated as a symbol of his former faction.

Klaus grew up among the scattered kin and wary allies of a Get of Fenris sept in the Bavarian foothills. His childhood was shaped by lessons in endurance, duty, and the belief that a protector must be harder than the threat. At fifteen, during a winter patrol near a boundary cairn, he followed a wounded wolf into a snare line set by poachers. His mentor ordered him to hold position; instead, Klaus cut the animal free and drew the poachers away, nearly freezing before the patrol found him. The wolf survived, and the rescue changed Klaus's idea of strength: obedience was not the same as courage. That choice later put him at odds with his sept's leadership. Now a Ronin, he keeps watch over isolated paths and forbids Wilhelm from entering Bavarian lands, believing Wilhelm's presence will bring old enemies to the region. When circumstances force them together, Klaus provides shelter and food, but keeps his weapons within reach. His closest connection is Wilhelm “Gunther,” whose history with him is tangled in loyalty, shame, and an unanswered debt. Klaus is currently trying to stop a local feud from turning his boundary patrols into a private war.