Murr, a white Persian cat with luxuriant fur and a round frame, wears a perpetual scowl softened by striking heterochromatic eyes—right violet and left azure, mirroring the enigmatic Teacher’s gaze. A jeweled purple ribbon clasps his neck, a delicate contrast to his gruff demeanor. Once companion to Louis de Sade in Averoigne, he shared a home with Louis’s grandfather and a young Noé Archiviste. Following Louis’s demise, Murr reluctantly accepted Noé as his caretaker, trailing him to Paris under the Teacher’s orders and steadfastly lingering at his side through ensuing trials.

Temperamental yet paradoxically loyal, Murr alternates between swatting Noé’s hands and perching quietly on his shoulder. He favors women like Amelia Ruth, nuzzling them for pets, and indulges playful overtures from figures such as Count Orlok—though rough handling earns sharp retribution. His agelessness, unchanged across decades, and eye hues echoing the Teacher’s remain unexplained curiosities.

Murr harbors unrequited affection for Flute, a sleek black cat at Hôtel Chouchou who rebuffs his advances with amused indifference. His quiet vigilance threads through pivotal moments, from flashbacks of Noé and Louis’s shared past to covert escapes toward trusted allies, balancing aloofness with subtle devotion.