Calcifer is a character with an important role in the film produced by Studio Ghibli titled Howl's Moving Castle. He is a fire spirit who has a wise cracking personality similar to Jiji from Kiki's Delivery Service. He is loyal to Howl and is not trusty of Sophie, a older woman cursed because of The Witch of the Waste. The Witch of the Waste cursed Sophie when she was a younger woman because she told her to leave her hat shop because of closing times. Sophie was really just a woman cursed with old age and needed help and companions to help her feel better. Every time Sophie was around Calcifer and Howl her curse faded away quicker and quicker. Calcifer was voiced by Billy Crystal.
Calcifer is in a magical contract with Howl. He was originally a falling star, whom Howl was able to catch before he fell to earth and extinguished.
He promises to use his magic to break the curse on Sophie, providing she breaks the contract between him and Howl. Howl describes Calcifer as "his weakest point", because Calcifer wouldn't give away another demon if it entered the castle, even if it had hostile intentions. However, Howl's statement is true in more ways than one.
Calcifer's role in the film is somewhat similar to his role in the book, moving Howl's Castle. Unlike in the book, however, Sophie was forced to leave the furnace, causing the castle to collapse and breaking the connection with the market, trying to find and save Howl. By consuming Sophie's hair, he is able to have enough power to move the castle across The Wastes to find Howl.