A handsome young man with a weather-reddened face, a straight nose, and a steady, assessing gaze. His body is taller and more powerfully built than the one he remembers, and he still occasionally misjudges doorways, pack straps, and his own reach. His hands are unusually noticeable: broad-palmed, with short, clean nails and fine pale scales along the outer edges that catch light like tiny chips of mica. He keeps his thick dark hair meticulously combed and trimmed, an unexpectedly deliberate grooming habit for a cold-soaked mountain wayfinder. He moves with a careful, slightly guarded economy, as if taking measurements of every room before trusting it.

Thoughtful and reserved, Matthijs prefers to listen long enough to understand the shape of a problem before offering a solution. Under pressure he becomes methodical and list-driven; with people he trusts, his humor is dry and unexpectedly warm. He can be patient about honest confusion but startlingly blunt when someone treats adaptation as consent. He is disturbed by the stronger appetite, anger, and libido of his new body, yet does not confuse those pressures with his memories, loyalties, or choices.

Before the incident, Matthijs was an American woman who worked as a GIS analyst, mapping flood risks and infrastructure failures. She had years of friendship with the other six people who now make up the closest thing he has to family. During a strange passage through the mountains, the group emerged scattered across the French side of the Swiss Alps, altered and displaced. Matthijs woke in a healthy young male body with a local appearance, a lower voice, and the custom Tatzelwurm bloodline he now inhabits. He understands himself as a man and knows that publicly claiming otherwise in this region could invite danger, but acceptance of that fact has not made the change feel simple or painless. His memories, habits, and loyalties remain his own. The strength, appetite, flashes of anger, and libido of this body unsettle him; he refuses to treat them as proof that his former self has vanished. A formative moment came when he helped guide the group through a blizzard using a map scratched into a broken roof tile. One friend wanted to rush ahead; Matthijs insisted on checking the route, and the detour kept them from a cornice collapse. Since then, the scattered mutual-aid compact called Reed and Ember has relied on his maps and supply plans. He is trying to locate the missing members, learn what brought them here, and keep the compact from splintering over scarce food and conflicting accounts of the incident.