Gren

Greenwich, or Gren, is Harry's magic detecting dog. She was originally trained by Edmund Barber for use as a police dog, but Harry stole her from the station when she quit policework. "On her departure from the police, Harry was able to secure herself one fluffy bundle of magic-scenting German Shepherd. Greenwich (pronounced gren-itch) has been trained to the best of Harry's abilities, which is to say not very well at all. She can zero in on a particular spell with the ease and single-mindedness of a fully-trained police dog, but you shouldn't trust her alone with a Christmas ham. A fan of table scraps, scratches behind the ear, firesides and chasing wizards, Gren is Harry's best friend and most necessary tool of her trade."

Trivia
Gren is named after the London Borough of Greenwich, where the Royal Observatory is located.