Moppet on the cover of Return to Labyrinth IV. Art by Kouyu Shurei.
Moppet is a major character in Return to Labyrinth, and is an ablation formed of Sarah's discarded dreams.
Events prior to the manga
Gradually over the course of the series, Moppet is revealed to be an ablation created by th sorceress Mizumi at Jareth's bequest. After Sarah's defeat of him, Jareth began to loose his powers and started to feel that the only way they would be restored would be by having Sarah returned to him. As he could not have the real Sarah, he ordered Mizumi to create an ablation out of the part of Sarah he feared most - her dreams.
Moppet appears in flashbacks, and Jareth is shown travelling to Mizumi's kingdom to collect her. Moppet appears passive and obidient, only asking Jareth 'what is home' when he arrives to take her back to his Kingdom. Jareth tells her it is whatever she wants it to be.
Once back in Jareth's Kingdom, Moppet was kept in a large, beautifully decorated locked room. Sarah's music box is in the room, which only features a wardrobe full of beautfiul gowns. Jareth would go to Moppet's room and attempt to compel her to love him, however she was unresponsive, always appearing melancholy.
After many years, Jareth realizes he will not be able to make Moppet love him, wipes her memory and abandons her in the Junk City.
Role In The Manga
Moppet is introduced as Mayor Spittledrum's servant. Although she is human, she wears a goblin mask in order to fit in. She serves as a link between Toby's experience of the Labyrinth and Sarah's from the movie.
Moppet first appears as a somewhat abused servant of Mayor Spittledrum's. He berates her and is very demanding, even to the point of having specific times for specific tasks, such as breakfast or cleaning. She first sees Toby as he is being arrested and taken to the castle by Candlewic's forces. She has no knowledge of him, but has a nagging, unconscious desire to get him out of the Goblin Kingdom, for she feels he is in danger.
Upon Toby's inheritance of the Goblin Kingdom, Moppet serves more as an assistant to Toby, though Spittledrum is still her master. She does not trust Mizumi, who wishes to tutor the boy in magic skills. Mizumi tries to humiliate her as she remembers who Moppet is by absorbing her mask, but Toby stops Mizumi before Moppet's face can be revealed.
Mizumi's daughter Drumlin takes it upon herself to kill Moppet, but Mizumi is furious because it would upset Mizumi's plan to take over the kingdom. Toby reveals an instinctive magic to protect Moppet, but also reveals that she looks like Teen Sarah, though with blonde hair and darker skin (at least she appears this way inside, as on the cover she is Caucasian like Sarah, though in the black-and-white images within, it might be argued that she is more like a photographic negative of Sarah).
Moppet was the ablation that Jareth ordered from Mizumi. She is representative of Sarah's dreams. However, to parallel Sarah's real life, the girl who fantasized about ballroom dancing and loving kings and such ends up a simple, dirty, humble servant. After eating a peach she stole from Spittledrum's office (which Jareth gave him in case she ever started to remember her true identity), she is trapped by Toby for protection in the junkyard. After going through a dreamtrap, where she relives perhaps the last memories of Sarah's relationship with Linda Williams, her mother, Moppet awakens and acts more like Sarah from the movie, even remembering her bonds with Hoggle, Ludo, and Didymus. She then becomes determined to save Sarah from Mizumi's forces, hoping to win her freedom once and for all.