Xehanort

Master Xehanort is the original master of Ventus, the creator and master of Vanitas, and the original incarnation of Xehanort. He is a Keyblade Master and the main antagonist of Terra's story in Kingdom Hearts Birth by Sleep.

Kingdom Hearts Birth by Sleep
''One of the true Keyblade Masters and a longtime acquaintance of Master Eraqus. He is connected with the masked boy, and harbors a hidden agenda.''

Unlike Master Eraqus, Xehanort believes darkness need not be rejected if it can be controlled.

Kingdom Hearts Birth by Sleep
In his youth, Xehanort, who once lived on a beach, had dreams of leaving his home in search for something greater. At some point he found a way to depart his home world and was trained to be a Keyblade Master, eventually befriending Eraqus, another Keybearer. Throughout his life, Xehanort traveled to many different worlds and obtained vast knowledge concerning Keyblade lore, the power of Light and Darkness, a detailed knowledge of the Heartless, the mysteries of the Keyblade War and Kingdom Hearts. Realizing the power unlocking the "heart of all worlds" would grant, Xehanort set his goal on finding a way to open the door to Kingdom Hearts.

By the time he discovered a way of opening that door, Master Xehanort had grown old, and realized that he must transfer his essence and knowledge to a "new vessel" in order to survive to see his plans reach fruition. To this end, he sought out an apprentice and found the boy Ventus, who he began training as Keyblade wielder with the intent of pitting him against one of Master Eraqus' students to forge the χ-blade, a legendary Keyblade capable of unlocking Kingdom Hearts. However, Ven was too weak and a poor candidate, so Master Xehanort decided to instead use him as part of his ultimate plan. By using his Keyblade to split Ven's heart and create a being with a heart of pure light and a being with a heart of pure darkness. The being of light remained as Ventus, while the dark being assumed the name "Vanitas". With these two boys, Master Xehanort intended to forge the χ-blade.

Unfortunately the process left Ven in a comatose state with his broken heart of pure light slowly fading out. Master Xehanort (in a black coat) decided to leave Ven to die in a peaceful setting in his old home, the Destiny Islands. To his master's surprise, Ventus's heart somehow survived and Xehanort realized the boy could still be of use. However, Ventus was still far too weak in comparison to Vanitas, for the two needed to be equal in power for the creation of the χ-blade. Additionally, Xehanort realized that he could not train Ventus and Vanitas together, as Vanitas' darkness would eventually consume and completely destroy Ventus' light. Master Xehanort ultimately left Ventus in Eraqus' care, to let him train and grow stronger.

At this point, Master Xehanort set his eyes on one of Master Eraqus's apprentices: Terra, within whom he sensed the correct potential to be his new vessel. While in the Land of Departure, Master Xehanort sabotages the Mark of Mastery Exam taken by Terra and Aqua, causing Terra to fail, and later tells him that if he were to become a true Keyblade Master, he would have to embrace the darkness in his heart rather than fight it. Shortly thereafter, Master Xehanort and Vanitas disappear on an apparent quest to find the Princesses of Heart.

During his travels, Master Xehanort manipulates Master Eraqus's apprentices (Terra, Aqua, and Ventus), who had been sent to find him and destroy the Unversed, a malicious species created as a side-effect of Vanitas's existence. He encounters Terra in the Keyblade Graveyard and puts his manipulative skills to the test, explaing the reason for his actions: He is trying to safeguard the light from the "demon" he unleashed. He then goes on to explain Vanitas's origins, how he was accidentally created when Master Xehanort tried to save Ventus from succumbing to darkness by removing the darkness from him. Unfortunately, the process severely damaged Ventus's heart, so out of guilt, Master Xehanort left Ventus under Eraqus's care. Lying that Vanitas is responsible for the whole chaos of the Unversed, Master Xehanort pleads with Terra to help right this wrong by destroying Vanitas. Terra agrees, and is instructed to search in the Radiant Garden

He next travels to the Radiant Garden and strikes a bargain with Braig (who desires the Keyblade for himself), Master Xehanort stages his own capture and has Braig fight Terra, with Terra succumbing to the darkness and injuring Braig, blinding the young man in the right eye and scarring his face. Master Xehanort tells Terra that he shows the true Mark of Mastery as he was able to channel the darkness instead of rejecting it and that Eraqus will never accept it out of his fear of darkness. He then goes on to state his belief that light and darkness are a balance that must always be maintained. He then gives Terra an opportunity to be his pupil, claiming that they can do the worlds much greater good by wielding light and darkness in equal shares. Master Xehanort then pulls the final string, calling him by the name "Master Terra" and gaining the young man's trust.

Later on, Master Xehanort has Vanitas abduct Mickey Mouse as bait to lure Ventus to the Keyblade Graveyard, where he reveals to him the truth about his past, stating also that Master Eraqus knows about it. While Ven goes to see Eraqus, Xehanort tells Terra that Eraqus has gone mad and is about to destroy Ventus. Terra is tricked into defeating Master Eraqus in battle, allowing Xehanort to callously deliver the finishing blow to his former friend. Master Xehanort then tells Terra to go to the Keyblade Graveyard where he will see Aqua and Ventus for the last time before falling prey to the darkness. He then covers the Land of Departure in darkness, completely destroying the world and leaving nothing but the castle's remains, telling Terra he would not need a home where he is going.

Soon enough Terra, Aqua, and Ventus discover the truth and confront Master Xehanort and Vanitas at the Keyblade Graveyard (the remains of the legendary Keyblade War). There, Master Xehanort reveals to them his true plans to create the χ-blade and unlock Kingdom Hearts. In the ensuing battle, Master Xehanort freezes Ventus and has Vanitas knock Aqua out cold, while gleefully telling Terra that he is powerless to save them, causing Terra to lose control of his anger and succumb again to the darkness in his heart.

Terra uses the power of darkness to defeat the elderly Keyblade master, but Xehanort enacts his final scheme and uses his Keyblade to unlock his own heart and transfer it into Terra's body, prolonging his life and transforming him into the new Xehanort while his original body fades out of existence with a triumphant smile.

Blank Points
The hearts of Master Xehanort and Terra are (at the time) shown disputing over internal dominance within the new Xehanort. Despite Master Xehanort's insistence that he will soon incorporate Terra's heart into his own, Terra remains confident that he will win over Master Xehanort, who realizes that Terra is harboring the heart of Master Eraqus. Despite this, Master Xehanort shows no concern, and reveals to Terra that he has backup plans should his possession of Terra fail.

Kingdom Hearts coded
After Mickey returns to the Mysterious Tower with the news that they have located Ventus, Yen Sid explains that the destruction of Ansem and Xemnas will result in the restoration of Master Xehanort.

Appearance
Master Xehanort appears as an old man, bald except for thin eyebrows and a curled, silver goatee. His ears are pointed and his eyes are yellow. He has broad, hunched shoulders and a crooked back. He overall appears as a somewhat feeble old man, certainly deceiving given his immense power.

His attire is nearly identical to the clothes that Ansem, Seeker of Darkness wears, namely, a white and black cloak with a red inner lining, a white shirt with two thin black belts, white gloves and calf-high black boots, similar to those worn by Ansem the Wise's apprentices. The only major difference in appearance between them is that Ansem has his chest bared, along with his emblem on the front, while Master Xehanort does not. There are a few minor changes as well - Ansem's cloak has a gold lining on the edges, while Master Xehanort's cloak has black ones. This is later carried on to Ansem, explained because this particular Heartless was made from the heart of Master Xehanort.

Master Xehanort's previous attire is briefly shown as a Black Coat, possibly as a predecessor to the attire of Organization XIII.

In his youth, Master Xehanort had mildly tanned skin, golden eyes, and silver hair which both slightly spikes and falls past his shoulders in the back; it is styled similar to Xehanort's, albeit with four bangs framing his face - the back two thicker than the front two - and the two backwards spikes on the sides are absent, the topmost one slicked back. He wore the same style of white shirt, which only reaches to his thighs, a black vest with a high collar, long armbands which cover his forearms, and dark grey pants stuffed into his boots, similar to those worn by Organization XIII but absent of the silver lining on top, much like those worn by the guards of Radiant Garden.

Personality
Much like Xehanort, "Ansem", and Xemnas, Master Xehanort is shown to be a cunning, callous, and pragmatic being with the sole goal of merging with Kingdom Hearts, the lives of innocent people and even his closest friends meaning absolutely nothing to him. To this end, he is willing to put whatever he pleases on the line or destroy anything in his way, demonstrated when he manipulated several characters such as Terra, Aqua, Ventus, Braig, and even Maleficent; creates Vanitas, a sentient being for the sole purpose of forwarding his evil plan; and slays his old friend, Master Eraqus, in cold blood after tricking Terra into defeating him in battle.

His personality, at times, contradicts itself. His past shows that he was once a noble man who willingly took Ventus as his apprentice and cared for him until he started to lose his grip on sanity. After Ventus's heart is severely damaged by his separation from Vanitas, Master Xehanort took pity on him and brought him to the Destiny Islands, and eventually left him in Master Eraqus' care. At a later time, he even expresses genuine joy in one of his reports when Eraqus personally asked him to oversee Terra and Aqua's Mark of Mastery exams, in addition to expressing remorse for scarring Eraqus' face during their dispute over the χ-blade. At the end of the game, however, he appears to have put most of his good points behind him, shown when he stabs his old friend Eraqus in the back, completely destroys the Land of Departure, nearly kills Ventus by encasing his body in ice and throwing him off of a cliff and with his cold-hearted manipulations.

Overall, Master Xehanort is arguably the catalyst of all the events in the series so far, and could even be seen as the true villain of the Xehanort Saga. He shares most of his personality traits with Xehanort (before the latter's fight against the Lingering Sentiment and Aqua) and "Ansem", while Xemnas appears to be influenced several times by Terra's characteristics. He has a few unusual tendencies and quirks, however, such as turning away from the people he speaks to, or over-dramatizing his hand gestures when delivering a speech, even flexing his fingers in an unusual manner, as if itching to grab something.

Abilities
His age often causing opponents to underestimate him, Master Xehanort is a skilled Keyblade master and magic user. Able to teleport if he is in danger, Master Xehanort strikes opponents with powerful, fast-paced combos. He also can bombard foes with Thunder, Blizzard, and Earth-based magic. His magic skills are some of the most advanced seen in the series so far, able to create massive rock formations and pillars, encase Ventus's body in ice, project a gust of wind powerful enough to send Ventus and Mickey flying from his hand, block Braig's Arrowgun shots without raising his arms, and telekinetically control the Keyblades covering the Keyblade Graveyard to attack Terra and Aqua. He also possesses physical strength sufficient enough to grab a fully-armored Ventus by the back of the head and lift him into the air with one hand.

Master Xehanort shows a great deal of skill in utilizing the heart and its capabilities, able to create a living being, Vanitas, out of the darkness of Ventus's heart when he unlocks it and even able to direct his heart into Terra's body to possess it after his defeat in the Keyblade Graveyard.

Once he becomes the young man known as Xehanort through the possession of Terra's body, Master Xehanort proves to be the stronger of the two hearts residing within him. Master Xehanort's overpowering Terra's is demonstrated several times during the battle between Terra-Xehanort and Aqua, Master Xehanort's influence beginning the fight in the first place and even releasing Terra's heart from within the body of his younger incarnation when Terra begins to regain control.

Weapon
Master Xehanort is able to wield his Keyblade with great professionalism despite his age, and enough of his strength has remained over the years that he is able to use it in fast-paced physical combos. His battle pose is similar to that of both Vanitas and Riku, but he mainly allows the Keyblade to hang loosely at his side as he walks slowly towards opponents. Master Xehanort also uses his Keyblade to unlock countless hearts, including his own.

When Master Xehanort possesses Terra's body to become Terra-Xehanort, he abandons Terra's Keyblade and replaces it with his own. Terra-Xehanort wields the weapon with great skill, combining several of Terra and Master Xehanort's abilities to form his own deadly combos. As this Keyblade was gained by Terra-Xehanort through Master Xehanort's heart's more powerful influence, it is also used through Master Xehanort's influence to unlock Terra-Xehanort's heart.

Quotes

 * "This world is just too small."
 * "Empty creature from Ventus riven... to you, the name Vanitas shall be given."
 * ""χ"... A most ancient letter. Some say "kye," but the meaning is the same. Death... A letter that spells endings."
 * "Behold... These lifeless keys used to be full of power— united with the hearts of their masters. On this barren soil, Keyblades of light and darkness were locked in combat...as a great Keyblade War raged."
 * "Countless Keyblade wielders gave up their lives, all in search of one, ultimate key. And it will soon belong to me... χ-blade."
 * "You see how powerless you are to save them? Savor that rage and despair. Let it empower you!"
 * "Why I did him a favor and freed the darkness inside him, alas, poor Ventus never had the fortitude for such strenuous trials."
 * "Let all that anger out, my boy. Give your heart over to darkness!"
 * "Still so blind... Then I will make you see!"
 * "If you could have seen the fury in his eyes... I'm certain he's capable of anything. I fear the boy will force the truth out of Eraqus."

Trivia

 * Tetsuya Nomura stated the relationship between Master Xehanort and Master Eraqus is something like old classmates.
 * In the English version of Kingdom Hearts Birth by Sleep, Master Xehanort is voiced by Leonard Nimoy, who was chosen by Tetsuya Nomura specifically for his role as Spock in the Star Trek franchise. This was Nimoy's final acting role before his retirement in 2010.
 * In the Japanese version of Kingdom Hearts Birth by Sleep, Master Xehanort is voiced by Chikao Ohtsuka, who was chosen by Tetsuya Nomura specifically because he is the father of Akio Ohtsuka, the Japanese voice actor of Xehanort and "Ansem". Chikao Ohtsuka also previously voiced Captain Hook in the original Kingdom Hearts but was replaced by Naoya Uchida for Kingdom Hearts Birth by Sleep.
 * In Kingdom Hearts Birth by Sleep, Yen Sid states he had hoped Master Xehanort's Heart wouldn't lead him astray again. This is a sign that the two have possibly met before, as Yen Sid is revealed to be a former Keyblade Master and an acquaintance of Master Eraqus.
 * Tetsuya Nomura has confirmed in interviews that the final game of the Xehanort Saga will feature Master Xehanort's final battle against Sora.
 * The first few sentences that Terra-Xehanort says after coming into existence are a nearly word-for-word quote of what Ansem says when Sora finally confronts him in the original Kingdom Hearts.