Fai D. Flowright (ファイ・D・フローライト Fai D. Furōraito?, Romanized in Japanese as "Fay D. Flourite") is a powerful magician from the country of Celes. He travels to Yūko on his own accord after sealing his king Ashura-ō and having his creation, Chī, alert him if Ashura awakens. He wishes never to return to his country, so he gives up a tattoo on his back in exchange for Mokona to travel through dimensions. Having lost his tattoo, Fai decides not to use magic anymore and relies on weapons to battle. Fai appears to be cheerful and good-natured, and acts very carefree. He often teases Kurogane, who questions this nature, sensing that it is just a false persona to hide that he is emotionally distant. Fai does not bother to fight hard for his life, and will only do so if someone he cares for is in danger, which Kurogane notes to be Syaoran and Sakura, as he uses magic to help them. He is voiced by Daisuke Namikawa in the anime adaptation, and by Vic Mignogna in the English adaptation.
Fai's real name is Yūi (ユゥイ?), and he was born with his identical twin brother, Fai, in Valeria Country. The birth of twins in the country was a bad omen, which led to many misfortunes upon the country. The king imprisoned them within a tower, just before he killed everybody in the country. Eventually, Fei-Wang Reed appeared and offered to free one of them. Fai chose to save Yūi, resulting in Fai being thrown from the tower to his death, though Fei-Wang tampered with Yūi's memory to make him think that he chose his own life over Fai. Promising to return Fai to life if Yūi becomes his pawn, Fei-Wang bestowed two curses upon him. The curses are to kill whoever is a stronger magician than he is, and another curse will use his magic to collapse the world around them. He was soon found by Ashura-ō, who took in Yūi, having adopted the name Fai. Ashura conforted Fai, and gave him his tattoo to suppress the first curse. Fai eventually learned that Ashura's purpose was to be killed by Fai's first curse, as Ashura killed people in order to make his magic stronger.
The source of Fai's magical powers is the blue color of his eyes that allow him to perform spells, which also greatly increases his lifespan. His powers are effectively halved when Syaoran consumes his left eye and is forced to become a vampire using Kamui's blood to save his life. He gains regeneration, though he has to regularly drink Kurogane's blood. He later gives up the rest of his magic in order for Yūko to restore Kurogane's lost arm with a mechanical one. Later he recovers his lost left eye when the clone Syaoran is killed by Fei-Wang. Following Fei-Wang's death, he, Kurogane and Mokona decide to accompany the original Syaoran in a journey who is unable to stay in every dimension for a determined time. In Clamp's Kobato. anime and a xxxHolic chapter, Fai makes a guest appearance along with the original Syaoran, Kurogane and Mokona.