Heen

Hin (pronounceded Hee-n) is a small and very ancient white and brown dog who appears only in the movie. He works for Madame Suliman as an errand runner and an inconspicuous, though unreliable, spy. He appears to replace Percival from the books. The small white dog Waif seems to be a nod to the character from the movie.

Howl's Moving Castle (Movie)
Heen, Madame Suliman's personal errand-dog, is sent out from the palace to escort Sophie Hatter, who is posing as Howl's mother. However, Sophie thinks that Heen is Howl Jenkins Pendragon in diguise, so begins a one-sided conversation with him, and even drags him up the endless stairs to the palace with her. Heen leads her away from the Witch of the Waste through a secret entrance to Madame Suliman herself.

Madame Suliman reveals the dog's true nature during their discussion, which certainly surprises Sophie but she doesn't voice this. She then explains that she has drained the Witch of the Waste's maigical powers, restoring her to her original appearance, a harmless old lady. This is when Howl comes into the palace, disguised as the King.

When they make their escape from the palace, Heen jumps onto their Flying Kayak just as they take off, and comes to the castle with them. He lives there for some time, doing nothing more, it seems, than act as a family dog.

When the castle collapses after Calcifer is nearly extinguished, Heen jumps after Sophie, and points out to her that her ring is glowing when she is too grief-stricken to notice. He leads her into Howl's past through the door, and leads her back out when their journey into the past is over.

At the end of the movie, Madame Suliman is shown looking into the orb in her staff to see him, asking him why he did not report in earlier, implying that she sent him to go with Sophie to act as a spy in Howl's Castle. He reveals the scene behind him of a happy ending, for which Suliman calls him a "little traitor," though does not seem terribly upset.