Xaro Xhoan Daxos is a merchant of Qarth. He is first seen in the book A Clash of Kings, when he comes along with Pyat Pree and Quaithe to invite Daenerys and her small khalasar who had taken refuge in an abandoned city to come to Qarth.
He has Daenerys stay as a guest in his home and frequently tries to persuade her to marry him, but he merely wants one of her dragons; it is a law in Qarth that, after marriage, each spouse may ask the other for one gift, and the other must oblige. He advises her on how to persuade the nobles of Qarth to give her ships to invade Westeros, but she is unsuccessful. Daenerys continues to refuse to marry him and eventually he loses patience and asks her to leave, but politely.
It annoys Daenerys that he can cry at will and that even while professing his undying love, he is more interested in staring at his male slaves than at her. When Daenerys is in Mereen and surrounded by enemies, he comes to offer her ships if she will take them and leave for Westeros so that the slave trade can resume.