Vanitas

Vanitas is a Keyblade wielder and one of the primary antagonists in Kingdom Hearts Birth by Sleep. He is the apprentice of Master Xehanort. Created by Master Xehanort, Vanitas is the embodiment of the extracted darkness from Ventus's heart, and the progenitor of the Unversed.

Kingdom Hearts Birth by Sleep
Four years before the events of Kingdom Hearts Birth by Sleep, Ventus served as Master Xehanort's apprentice. The Keyblade wielder was sent to the Keyblade Graveyard, where he was forced by his master to face several Heartless. Ventus refused to use his darkness, and was knocked unconscious. Master Xehanort then proceeded to use his Keyblade to unlock Ventus's heart, extracting the darkness within and resulting in an orb of dark energy forming into a young boy in a mask who is then given the name "Vanitas" by Master Xehanort. The dark enigma would be the source of the Unversed, as well as a key component in Master Xehanort's plans.

After Master Xehanort views the battle between Terra and Aqua as part of their Mark of Mastery exam, he leaves the room to find a hidden Vanitas awaiting him. The two converse about Ventus, and Vanitas claims that Ventus' performance was weak, and he still needs to "break that loser in." Master Xehanort instructs him to do so somewhere else as he needed to keep up appearances. So Vanitas decides to give Ventus an "incentive" to leave home. Vanitas later appears before Ventus in his room, speaking of Terra being a different person, and that Ventus should follow him before it's too late. Ventus becomes very defensive, saying that Vanitas does not know the first thing about Terra, and that they will always be friends. Vanitas, disgusted, simply mocks his friendship with Terra, telling him to grow up and vanishes into a corridor of darkness, claiming that unless Ventus sees it for himself and looks beyond his "tiny world", he will not know the truth.

Vanitas then travels to different worlds, spreading the Unversed across them to make Ventus stronger for the X-Blade's forging. He is first seen with the Unversed in the Castle of Dreams world.

After his first few ventures throughout the worlds, Ventus spots Vanitas in space and is lured to the Keyblade Graveyard. Ventus interrogates him about what he meant about Terra being a different person. Vanitas simply reiterates what he said before, that Terra will be gone forever, and challenges him to a duel, intent on testing his power and revealing for the first time he is a Keyblade wielder. Despite Ventus's best efforts, Vanitas gains the upper hand mid-way, knocking Ventus down. Vanitas then prepares to eliminate Ventus, deeming the boy too worthless to be of use (even though it goes against Master Xehanort's plans), but before he could do so, Mickey Mouse appears, healing Ventus. Mickey Mouse then reprimands Vanitas for using his Keyblade to bully others. and the two then proceed to fight Vanitas, who simply shrugs off the fight and leaves yet again upon his defeat, claiming that Ventus is on "probation".

After the battle against the Trinity Armor in Radiant Garden, the ensuing argument forces Terra, Ventus, and Aqua to go their separate ways. While Aqua is in the Central Square, Vanitas appears, taunting her by calmly inquiring about Ventus and if he has gotten stronger. When Aqua asks what he means, Vanitas, in a more hostile tone, states that he is asking the questions as he claims he will be the only one who will walk away alive, and attacks, the two fighting a vicious battle with Aqua as the victor. After the duel, Aqua attempts to remove Vanitas's mask while he is unconscious, but her fingers barely reach the tinted glass before the dark enigma startles her with an insane laugh. He then compliments her skill and congratulates her on her victory, making an ambiguous comment about her being his backup plan, revealing that it was all a ruse to test her strength. He then leaves in another corridor of darkness.

While in Neverland, Vanitas encounters and kidnaps Mickey Mouse on Master Xehanort's orders to use Mickey as bait to lure Ventus back to the Keyblade Graveyard. Though the fight is not shown, it is clear Vanitas won. The villain later crosses paths with Aqua again, this time with Ventus's cherished Wooden Keyblade. Vanitas cruelly mocks Aqua for playing treasure hunter with the Lost Boys, proceeding to tell her that, with Ventus' newfound strength, he has "outgrown" the Wooden Keyblade, and then snaps it in half, an act that both enrages and horrifies Aqua. Throwing the pieces aside, Vanitas also claims that he has outgrown his need for Aqua as his so-called "backup plan" and draws his Keyblade, intent on eliminating her. Aqua, outraged by the act of cruelty and at the thought of Ventus being in danger, calls Vanitas a freak and battles the dark enigma once again, soundly defeating him and knocking him unconscious. Aqua, exhausted by the battle, passes out, as a revived Vanitas takes the opportunity to escape once again.

Vanitas encounters Ventus again in Destiny Islands, after the latter is thrown through a portal summoned by Terra. Ventus initially tells Vanitas that he is through with him. But Vanitas simply tells him that since he is strong enough, Ventus can join with him to forge the χ-blade. Ventus refuses, claiming that the χ-blade cannot be forged if he does not fight. Vanitas, though slightly angered, remains unfazed, responding only with a cold statement that Ventus was once "too broken to talk back." Then, in the ensuing flashback, Vanitas explains his birth from the darkness in Ventus's heart, and how he took his place as Master Xehanort's apprentice. This causes Ventus great pain in regaining his memories. Vanitas challenged Ventus to come find him in the Keyblade Graveyard, the one and only place where the x-blade can be forged, where he threatens to kill Terra and Aqua and callously wonders how long Ventus will "play the pacifist." Ventus, haunted by Vanitas's deranged threats, and determined to end this once and for all goes to the Keyblade Graveyard.

When Terra, Ventus, and Aqua approach their final battle with Vanitas and Master Xehanort at the Keyblade Graveyard, intense battles ensue. The two villains meet up with the trio, and after Master Xehanort explains his plans, the trio armors up and Terra quickly charges towards them. Master Xehanort intervenes, however, blocking Terra's path with massive rock formations. As Terra continues to pursue Master Xehanort, Vanitas goes after Aqua and Ventus, riding on a cloud of Keyblades Master Xehanort created. The two fight valiantly against the dark apprentice, but not before Vanitas returns to Master Xehanort's side after Ventus is frozen. He battles Terra alongside Master Xehanort, who later commands Vanitas to go after Ventus and Aqua again.

Vanitas attacks Aqua from above, knocking her unconscious, and prepares to impale her through the chest while Ventus lies helpless and frozen. Ventus summons all of his willpower, however, and breaks out of the ice to face Vanitas in battle, defeating him once again. Vanitas compliments Ventus on his skill and finally reveals his face, explaining himself to be the source of all Unversed. Glowing with dark energy, Vanitas then summons several Flood Unversed to restrain Ventus as he proudly explains his plan: to spread the Unversed across the worlds, so Ventus could leave his home and grow strong enough to forge the χ-blade. He then forcefully integrates into him. In a burst of light, Vanitas and Ventus are transported to the Dive to the Heart. Ventus's pillar now hosts a picture of Vanitas alongside his own. Vanitas wields an incomplete version of the χ-blade.

Vanitas claims their union was incomplete, and they only managed to make a fraction of the χ-blade. He then tries to join with Ventus once again, but Ventus refuses, vowing to defeat Vanitas and destroy the χ-blade. The dark apprentice simply laughs maniacaly, confident in the fact that they both know that should the χ-blade be destroyed, Ventus's heart would vanish forever. However, Ventus rebukes him, saying he will fight for his friends no matter what, even if the price is his heart, despite Vanitas's mocking of his reason to fight. The two Keyblade wielders then begin a final showdown in the Dive to the Heart.

As Ventus battles Vanitas in their Awakening, Aqua and Mickey are forced in the Keyblade Graveyard to battle a Ventus possessed by Vanitas, evident in Ventus gaining Vanitas's golden eyes and bodysuit. Ventus-Vanitas summons the completed χ-blade, and tries to attack Aqua, only for her to be saved by Mickey. He then goes on to explain with psychotic glee that he plans to unlock Kingdom Hearts so the worlds can be connected and the legendary Keyblade War can begin again. Aqua, sick of Vanitas's nonsense, screams at him to shut up and confronts him in battle one last time. As Aqua defeats her possessed friend and destroys the χ-blade, Vanitas's metaphysical battle with Ventus comes to an end after he shatters the pillar on which they were fighting. Vanitas fades out of existence, taking all Unversed in existence with him and relinquishing his control over Ventus. Unfortunately, the victory is bittersweet, as Ventus loses his heart and falls into a coma in the process.

Personality
As a being created from the purest of darkness, Vanitas is proud, cold, calculating, cruel, and pure evil. Vanitas is arugably one of the most malevolent villains shown in the Kingdom Hearts series so far. Unlike other villains who are motivated by a lust for power or revenge, Vanitas is perfectly content with causing others as much pain and suffering as possible. The lives of others, incuding that of even Master Xehanort hold absolutely no value to him, he shows zero remorse for his actions, and has no qualms with taking their lives if he is so commanded. As a pragmatist, he will kill without a moment's thought or hesitation. Seen as how he ambushes Aqua in the Keyblade Graveyard and attempts to kill her.

Despite his loyalty to Master Xehanort, Vanitas has no qualms with disobeying the man's orders if he feels the need arises. A prominent example of this is his attempt to kill Ventus despite full knowledge that Master Xehanort needed Ventus alive for his plans. This is also ironic as Master Xehanort is the only person Vanitas shows any respect towards.

Vanitas' name is derived from the Latin word for vanity, quite suting given the boy's immense pride. He holds an extreme amount of arrogance in his abilites, beliveing his skills surpass all others. In his first confrontation with Aqua, he claims he will be the only one to walk away alive, even bursting into a fit of hysterical laughter upon defeat. Right before possessing Ventus, he claims the boy never stood a chance against him and Master Xehanort. When confronting Ventus for the final time, he laughs when Ventus declared he would destroy him and the X-Blade. During the final battle between him and Ventus, Vanitas directly states his belief that he is the superior half of Ventus' heart. While confronting Aqua for the final time he taunts her by sarcastically asking if she has given up, and tells her that she was just wasting her energy trying to stop her. This overconfidence in his abilites usually leads to his downfall as he underestimates his opponents while fighting.

Vanitas is also highly manipulative, knowing full well how to use others to further his, and by extension Master Xehanort's, goals. He uses a person's emotions to taunt or outright provoke them. This is seen when he plays on Ventus' friendship with Terra to lure him away from the Land of Departure, telling him that Terra will change for the worst. He also plays on Aqua's emotions to provoke her into battling him.

Vanitas is a very cruel and ruthless individual, having not the slightest sympahty for anyone but himself. Vanitas holds everything and everyone in contempt. This is seen in his frequent criticizing of Ventus' friendships with Terra and Aqua, when he cruelly mocks Aqua for playing with the Lost Boys and breaks the Wooden Keyblade right before her eyes, and his constantly calling Ventus "idiot." In addition to threatening to kill Terra and Aqua to force Ventus to fight him.

The Masked Boy is shown to be cool, calm, and collected. Showing no outward emotion until the end of the game, when he possess Ventus and creates the X-Blade. Even in the face of defeat, Vanitas remains tranquil. An example of this is his reaction to Ventus' refusal to forge the X-Blade. The only two times in the entire game when Vanitas loses his composure are when he possesses Ventus and declares his plans for the X-Blade, and when Ventus defeats him for the final time. He begins to panic and makes a desperate attempt to grab the floating X-Blade before dying.

Vanitas' overall personality is an extremely stark contrast to Ventus and Sora (as well as their extensions, Roxas and Xion.) who are valiant, heroic, and value friendship.