Mary Hudson, also known as Mrs. Hudson, is a central supporting character in the anime Sherlock Hound. She is the young, comely landlady and housemaid of 221B Baker Street, where she lives with the detective Sherlock Hound and his companion Dr. Watson. Unlike the traditional portrayal of an older, matronly figure, this version is a widow in her late teens, having lost her husband Jim, a pilot, during one of his missions. Her maiden name or full given name is Marie, but she is most commonly referred to as Mary or Mrs. Hudson in the series.

Her background as the wife of an aviator gives her strong ties to the aviation community, and she maintains friendships with her late husband's fellow pilots. These connections often prove valuable to Hound's investigations, providing access to airfields, aircraft, and information that would otherwise be out of reach. She is depicted as a golden retriever in the anthropomorphic animal style of the series.

In terms of personality, Mary Hudson is gentle, serenely dignified, and level-headed, displaying a calm composure that mirrors Hound's own demeanor. Beneath her polite exterior, she is resourceful and surprisingly capable in action. She is an excellent high-speed driver, able to handle car chases with skill, and a proficient sharpshooter with a revolver. These abilities allow her to actively participate in dangerous situations rather than merely waiting on the sidelines.

Her motivations are rooted in loyalty and a sense of duty to her tenants, as well as a genuine affection for Hound. She takes her role as caretaker seriously, managing the household with efficiency and tolerating Hound's eccentricities with patience. She also harbors romantic interest in Hound, a feeling that is reciprocated to some degree, though the relationship remains understated. Additionally, she becomes a love interest for both Watson and Professor Moriarty, the latter of whom kidnaps her in one episode, mistakenly believing that harming her will weaken Hound. However, she proves herself more than capable of handling the situation.

Her role in the story is multifaceted. She provides domestic stability for Hound and Watson, but she also steps into the action when needed, using her driving and shooting skills to assist in cases. She is not merely a damsel in distress; rather, she is a resourceful ally who can be trusted with risky tasks. Her aviation connections are a recurring plot device, and she occasionally takes the initiative to help Hound when he is in a tight spot.

Notable abilities include her marksmanship, her expert driving, and her knowledge of aviation. She is also a keen observer and possesses a steady nerve, as seen when she is taken hostage and manages to outwit her captors. While she does not undergo a major character arc in the series, her consistent portrayal as a strong, capable woman who is both nurturing and brave makes her a memorable part of the ensemble.