Calcifer

カルシファー

Calcifer is a fallen star captured by Howl. Fearing death, he made a bargain with the wizard. Calcifer obtained Howl's heart and an extended lifespan, while Howl gained complete access to Calcifer's significant powers.
Eventually, neither party was satisfied with the arrangement, yet the contract could not be dissolved by those bound by it. When Sophie Hatter arrives at Howl's moving castle, Calcifer realizes she is cursed by the Witch of the Waste and possesses considerable, unrecognized powers of her own. To free himself from his own curse, Calcifer proposes to lift Sophie's curse on the condition that she breaks his contract with Howl.