Luxu

Luxu is a Keyblade Master who appears in Kingdom Hearts χ. He is an apprentice of the Master of Masters.

Kingdom Hearts χ Back Cover
Luxu is instructed to meet the Master of Masters in the Foretellers' Chamber, where he is bestowed with a Keyblade containing the Master's own "Gazing Eye". Luxu initially misunderstands that "Gazing Eye" is the name of the Keyblade, but the Master corrects him that it is unnamed, and Luxu names it "No Name" in jest. The Master explains that the Keyblade containing the Eye must be passed from master to apprentice so that the Eye can see events pass throughout the ages, prompting Luxu to realize that the Master's Book of Prophecies was written with the foresight from this process. In order to prevent temporal paradoxes, Luxu is not to receive a copy of the Book like the other apprentices, but is instead tasked with protecting the Black Box. The Master entreats Luxu to abstain from the conflict to come and instead simply observe events. As for the Box, the Master instructs Luxu to never open it or reveal its contents, but at Luxu's insistent questions, he whispers the box's contents to him, shocking and perplexing the boy.

Luxu then sets out to fulfill his role, disappearing as he travels through the Keyblade Graveyard with the Black Box and No Name in hand.

Kingdom Hearts χ
With the Keyblade War approaching, Ava seeks out Luxu to locate the Master in hopes of averting the cataclysmic event with the Master's aid.

Finding Luxu at the outskirts of Daybreak Town, Ava interrogates him, and he explains he is meant to continue on into the future written in the Book of Prophecies and see through the end of the world. Luxu surmises that Ava wants to avoid the Keyblade War and that she had sought him out in order to find the Master, and deems her efforts as useless. Luxu states that the Lost Page is a prophecy that the foretellers are not aware of and that it is his mission to inherit its secrets. Ava begins to suspect Luxu of being the traitor. Summoning his Keyblade, Luxu proceeds to tell her the truth about the traitor and questions Ava's resolve to stop the Keyblade War when it is unavoidable. Ultimately, Luxu states that even if there was another answer, that would still be the result of the battle and ponders if the Master would rather know how his disciples will guide the keys than the fate of the world. Ava, refusing to believe that the Master would choose them over the world, accuses Luxu to be taking his advantage of the Master's will. Drawing her Keyblade, Ava attacks Luxu, and the clashing of their Keyblades sends a ripple effect throughout Daybreak Town, which tolls the bell that signifies the beginning of the end.

Kingdom Hearts 0.2 Birth by Sleep -A fragmentary passage-
With the No Name Keyblade in his hands, Luxu silently observes the conclusion of the Keyblade War, granting the Master of Masters knowledge of the event.

Between Kingdom Hearts 0.2 Birth by Sleep -A fragmentary passage- and Kingdom Hearts III
Having been instructed by his master to transfer his heart from one vessel to the next until the fated "Dark Master" appeared to reenact the Keyblade War, Luxu's final role is to become an ally of this individual, Master Xehanort, and aid in his plans in order to continue to observe the future. Luxu eventually finds Braig as his final vessel for his heart. Braig's infatuation with the Keyblade is simply a cover used to join Master Xehanort and serve as his right-hand. With no knowledge of the future or the true extent of Xehanort's plans, Braig follows his master's orders loyally by assisting Xehanort when both serve as Ansem the Wise's apprentices, becoming a Nobody in the process, and aids the villain in recreating the Keyblade War and completing Kingdom Hearts.

Kingdom Hearts III
While Xehanort is destroyed by Sora and Kingdom Hearts is locked away once again, Luxu, in Xigbar's body, is able to reclaim his Keyblade and summon his old companions, the other foretellers with the exception of Ava, in the Keyblade Graveyard. Declaring that his mission is finally over, Luxu begins to tell the foretellers the long and complicated history of his role.

Design
Like the Master of Masters, Luxu wears a black coat, which completely obscures his features.

Luxu's name is derived from the word , which means "lust" in Latin.

Personality
Contrary to the Master of Masters, Luxu is quiet and reserved. However, by the time he inhabits Xigbar's body, Luxu is much more outspoken and sarcastic, in many ways emulating his mysterious master. Over time, the once quiet and honest Luxu also became much more secretive and deceptive, making vague statements and throwing his opponents off, such as when he told Sora he was worthy of a Keyblade simply because Xehanort promised it to him, not because it belonged to him.

Abilities
Luxu is a Keyblade Master who is given the No Name by the Master of Masters. Like Xehanort, Luxu has mastered the ability to transfer his heart into others, thereby claiming a new vessel to live on in, discarding the old one.

Through the gazing eye embedded in the No Name Keyblade, Luxu has been allowing the Master of Masters to watch history as it unfolds and record it into the Book of Prophecies, ensuring it happens the way he intends.