Percival (called Gaston) was a man cursed by the witch of the waste. He was created by leftover parts from Ben Sullivan and Prince Justin, that the witch got in her attempt to create her perfect man. She decided to make a servant and called him Gaston. Gaston was forced to obey the witch. He got access to Prince Justin's memories and remembered Lettie Hatter. When the witch learn of her, she got mad and demanded Gaston to tell everything he knew of Lettie. Gaston only managed to tell her about the hat shop that Lettie's family own and made it sound like it was Lettie's shop. The witch dragged Gaston to the shop and they found Lettie's sister Sophie. Believing Sophie to be Lettie the witch cursed her and turn her into an old woman. After which she turned Gaston into a dog and let him go loose. He ran over to Lettie Hatter and Annabel Fairfax and stay with them for a while. When Lettie learn of what has happened to Sophie Gaston promised her to look out for her and followed Sophie to Howl's castle, where he was turn into his man-shape. Calficer discovered that the last name he answered to was Percival so Howl and the other inhabitances decided to call him that.
- The name Percival might come from Prince Justin's memories who used many aliases in his search for Ben Sullivan.