Xaro Xhoan Daxos is a character from A Song of Ice and Fire and Game of Thrones, where he serves as an antagonist to Daenerys Targaryen during Season 2. He is a wealthy (though not as wealthy as he initially claims) merchant from the city-state of Qarth, and one of the rulers of the city known as the Thirteen. In the television series, he conspires with the warlock Pyat Pree and Daenerys' handmaiden Doreah to use Daenerys' dragons to become "King of Qarth".
In the novels Xaro is still alive and declared war against Meereen because Daenerys refused to leave Slaver's Bay for Westeros, much to his annoyance. Qarth is an ally to Yunkai, and the qartheen fleet joins with the yunkish army during the Second Siege of Meereen. The qartheen fleet is currently opposed by the Iron Fleet, led by Victarion Greyjoy
Game of Thrones
Xaro and the Thirteen meet Daenerys Targaryen at the gates of Qarth, weeks after the Thirteen met with Daenerys' bloodrider Kovarro. They demand to see her dragons and when she refuses they deny her admission to the city. Xaro invokes the ancient custom of Sumai to allow her and her people to be admitted under his protection. Xaro welcomes Daenerys to the city and makes her a guest in his expansive mansion. He makes repeated references to the fact that he came to Qarth with nothing, but by skill and determination has made himself the richest man in the city.
Xaro hosts a lavish reception for Daenerys in his gardens to introduce her around to Qarth's social elites, and showers her with gifts. Later that night, he shows her his massive treasure vault which is impossible to open without the key he always wears around his neck. Inside is his enormous fortune which he promises to divide with her if she will marry him. Xaro informs Daenerys that news has reached Qarth that King Robert Baratheon is dead, and the subsequent outbreak of the War of the Five Kings which is tearing Westeros apart. Daenerys learns that the major noble Houses which played an active role in deposing House Targaryen are now fighting each other: Robb Stark is fighting the Lannisters, and the Baratheons have been split between Robert's two younger brothers, Stannis and Renly.
Daenerys is at first excited by this news, as she has lived in fear of Robert Baratheon her entire life. More importantly, the outbreak of the War of the Five Kings means that House Targaryen's enemies are now divided. She seriously considers Xaro's offer of a marriage-alliance, as he can provide her with enough money to raise an army to invade Westeros with. Her advisor Ser Jorah Mormont is more hesitant, however, stressing that men like Xaro only want something in return. Daenerys acknowledges that Xaro has openly admitted that he hopes to become even wealthier if Daenerys reconquers Westeros as his wife, but Jorah points out that this won't simply be rewarding Xaro: the lords of the Seven Kingdoms will say that it was Xaro's conquest, achieved with resources he provided, and Daenerys will become little more than a figurehead.
Initially eager to take the quickest path back to Westeros, Daenerys eventually relents to Jorah's advice and decides to decline Xaro's offer for the moment. Instead she tries to secure support for her return to Westeros from his colleagues in the Thirteen, but without success. While they are meeting with the Spice King her dragons are stolen from Xaro's home. One of Daenerys' maids Irri is dead while the other, Doreah, is missing and presumed dead. Xaro uses the theft as a premise to hold a council of the Thirteen in his home. He then stages a coup with the assistance of the warlock Pyat Pree and declares himself King of Qarth. The warlock uses his magic to kill the rest of the Thirteen. They reveal that they stole the dragons and have taken them to the House of the Undying. Daenerys flees in terror.
Daenerys later escapes from the House of the Undying after retrieving her dragons and with her men invades Xaro's house where she finds Xaro in bed with Doreah, revealing that she had in fact betrayed Daenerys and her dragons to Xaro and Pyat Pree. Xaro and Doreah plead for their lives, with Xaro promising to get her ships to invade Westeros. Using the circular key pendant, the treasure vault is opened and found to be empty, his enormous wealth a lie to cling on to his power and seat. Xaro and Doreah are locked inside the merchant prince's vault to die, and Daenerys and her people ransack Xaro's house of all its gold and precious items, which Ser Jorah says will be enough to buy a ship.