and the city state of Helium. Although Tars Tarkas shows some civilization, he remains a noble savage. He is notable for a wry sense of humor invoked when he notices some irony in his present situation, as at his discovery of the Valley Dor. Kantos Kan: A soldier of Helium and Carter's friend, he is instrumental in organizing the Heliumite expedition to the South Pole, as well as thwarting Zat Arrras' plots. Xodar: A Black Martian, he was defeated by Carter just before Carter was first captured by the Black Martians, and because of his defeat by Carter, was degraded of all dignity by his own people and made Carter's slave. Thereafter, he serves as one of Carter's lieutenants, providing crucial aid due to his knowledge of the Black Martians' realm. Zat Arrras [sic]: A Zodangan prince who has been governing Helium in the absence of Dejah Thoris' father and grandfather, he is ambitious and jealous of Carter, hampering his efforts to return to Helium and reunite with Dejah. One of the main villains in the story. Thuvia of Ptarth: A Princess of Ptarth, rescued by John Carter from the Therns. She is later imprisoned with Carter's wife Dejah Thoris and Phaidor (see below) in a prison which can only be opened once per year. Typically of Burrough's heroines, she is tough, courageous, proud, and strongly identifies with her aristocratic position in Martian society. Phaidor: A high-ranked Thern girl, who becomes enamoured of John Carter and therefore envious of Dejah Thoris. Despite her love and regard for Carter, she is cruel and heartless like the rest of her race, which disturbed Carter. She is described as beautiful, but it is never specified whether or not she is bald like Thern males. Her attack on Dejah Thoris in the last chapter leaves a cliffhanger for the next book. Literary significance and criticism Many consider the first three books of the Martian series to be a trilogy. The books are a showcase of Burroughs’ talents: imagination, colorful descriptions, and adventure. Burroughs’ complicated and sometimes flamboyant prose, vocabulary, and grammatical constructions are surprisingly sophisticated for pulp fiction. Film adaptation Before the release of the 2012 film John Carter, producers Jim Morris and Lindsey Collins said that they were working on a sequel based on the second book, with the working title John Carter: The Gods of Mars. However, the film's poor box office