Character Analysis
When Howl finally notices that Sophie's dog is actually a dog-man under a curse, he insists on attempting to remove the enchantment. Unfortunately the enchantment is in layers though, and Howl and Calcifer can only take away the dog part. What they find when they strip away his dog curse is a guy who apparently can't remember his name or where he comes from. All that Calcifer can say is that he last answered to the name of Percival, and that he is made up from pieces of two people (…. ugh).
Percival doesn't have much of a character since he really can't remember much. The Witch brought him on errands with her, so Percival was there when she cursed Sophie—he was the horrified-looking red-haired man. It's through Percival that Lettie learns of Sophie's sudden onset old age. Once he is disenchanted, we find out that his affections for Lettie wind up in the Wizard Suliman, who decides to take Lettie as a magic student—and maybe something more.
We get a few hints along the way of Percival's real identity. He recognizes the flowers in the garden at the edge of the Waste, which means he must have been there before (the garden was built by Wizard Suliman), and when Percival picks up Howl's guitar, he tunes it and has it "sounding much nicer in seconds" (19.92). When Miss Angorian sees that guitar, she identifies it as belonging to Ben Sullivan (a.k.a. the Wizard Suliman). So when Percival gets his final curse removed and the Wizard Suliman appears, we aren't totally shocked.