TV-Series
Description
Fai D. Flowright is a powerful magician who joins the group of dimension-traveling protagonists in their quest. His real name is Yuui, and he was originally a prince from the country of Valeria, born alongside his identical twin brother, Fai. In Valeria, the birth of twins was considered a terrible omen, leading to the deaths of their parents and misfortunes that plagued the land. The king imprisoned the young twins in a pocket dimension within a tower, where they did not age. Eventually, the king became insane, killed all the other citizens of Valeria, and then took his own life in front of the imprisoned children.

After this tragedy, the enigmatic figure Fei-Wang Reed appeared and offered to free only one of the twins. Fai chose to save his brother Yuui, resulting in Fai being thrown from the tower to his death. Fei-Wang then altered Yuui's memories to make him believe he had sacrificed his brother to save himself. Fei-Wang cursed Yuui: one curse forced him to kill any magician more powerful than himself, and the other would cause his magic to collapse the world around him. He promised to revive Fai if Yuui became his pawn. Yuui was later found and taken in by King Ashura-ō of the country of Celes. Adopting his deceased brother's name, he became Fai D. Flowright.

On the surface, Fai presents a cheerful, good-natured, and carefree personality. He is often seen smiling and teasing his companion Kurogane with ridiculous nicknames. However, this easygoing demeanor is a carefully constructed facade that masks a deeply traumatized and emotionally distant individual. Fai carries a profound emotional burden and places very little value on his own life. In battle, he will not fight hard to save himself but will break his own vows to use magic to protect those he has grown to care for, such as Syaoran and Sakura. Kurogane is the first to sense that Fai's constant smiles are a disguise, and he often confronts Fai about his hidden unhappiness, leading to dark and enigmatic responses from the mage.

Fai's primary motivation at the start of the journey is to never return to his home world of Celes. He had sealed the sleeping King Ashura-ō and used his creation, Chii, as an alarm in case the king awoke. To escape, he traveled to the dimension witch Yūko Ichihara's shop and traded a magical phoenix tattoo on his back for the creature Mokona, who could travel between worlds. Without his tattoo to suppress his power, Fai vowed not to use his magic. He is highly perceptive, intelligent, and a skilled fighter even without magic, often using a staff as a weapon.

Throughout the story, Fai's role is that of a mysterious and powerful ally whose true past and loyalties remain hidden for a long time. He is revealed to have been acting as Fei-Wang's unknowing agent, possessing two of Sakura's memory-feathers that were crucial to the plot. His key relationships are central to his development. He shares a deep bond with Kurogane, which begins with Fai's teasing and Kurogane's gruff annoyance but evolves into a profound connection where Kurogane refuses to let Fai sacrifice himself. Kurogane is the one who forces Fai to live after a grave injury, a choice that transforms Fai into a vampire. Fai's affection for the younger Syaoran and Sakura also becomes genuine, causing him to break his rule against using magic to save them.

Fai undergoes significant development as the series progresses. In the Tokyo arc, the clone Syaoran consumes Fai's left eye, which is the source of half of his magic. Near death, Fai is turned into a vampire by drinking Kamui's blood, a decision made by Kurogane to save his life. As a vampire, Fai gains accelerated healing and claws but is forced to regularly drink Kurogane's blood to survive, creating an even deeper tether between them. This event forces Fai to confront his own will to live and the bonds he has formed, which he had always tried to avoid for fear of causing harm. His tragic childhood and the curses placed upon him are eventually fully revealed, leading to an emotional resolution where he overcomes his past.

Fai's notable abilities are rooted in his magic, which resides in his blue eyes and is primarily destructive in nature. This magic also greatly extends his lifespan. After losing his left eye, his power is halved. As a vampire, he gains superhuman strength, speed, regeneration, and the ability to extend his fingernails into claws. He later gives up the remainder of his magic as a price to restore Kurogane's lost arm, but eventually recovers his original left eye and his full magical power after Fei-Wang is defeated. At the end of the journey, Fai chooses to continue traveling through dimensions with Kurogane, Mokona, and the original Syaoran.