Xion is the Rank XIV member of the original Organization XIII, and appears in Kingdom Hearts 358/2 Days as one of the main protagonists and antagonists. She is not a normal Nobody, and is only a nominal member of the Organization. Because of this, she does not have a throne in Where Nothing Gathers, nor does she have a title or a breed of Nobody to control. Instead, she is an imperfect Replica of Roxas created from Sora's leaked memories as a fail-safe in case both Sora and Roxas proved to be useless to Organization XIII's plans. While this enables her to use the Keyblade, Xion's existence also halts Sora's progression of regaining his memories to fully awaken while in his pod, something which Naminé, DiZ, and Riku recognize.
As Sora's memories are the basis of her being, Xion initially resembles Kairi, who was Sora's strongest memory at the time of her birth, though her physical appearance eventually changes depending on who is viewing her and who they have connections with. Roxas, Axel, and Riku see her as Xion (and later as Sora), Xigbar sees her as Ventus, Xemnas sees her as Sora, while Saïx (and also Axel, initially) sees her only as a hooded doll. As Naminé stated while talking with Riku, Xion's face was originally blank, until Sora's memories found their way into Xion and she gained an identity.
Xion's name was coined by Tomoco Kanemaki, one of Kingdom Hearts 358/2 Days's scenario writers and the writer of the Kingdom Hearts novels. Tetsuya Nomura took a liking to it and notes that it has many meanings. Xion's name contains the Japanese words for "tide" (潮 shio ), fitting the oceanic naming theme of Kairi and Naminé, and Aster tataricus (紫苑 shion ), which, according to Japanese floriography, means "I won't forget you" or "remembrance". It is also revealed within the Secret Reports that her "original name" was "No.i", her ID as an experiment of the Replica Program. The "i" used here is in fact the imaginary number.
Xion was voted "Best New Character" in the 2009 Nintendo Power Awards.
 Kingdom Hearts 358/2 Days
A week after Roxas joins Organization XIII, Xemnas introduces Xion to the other members. After looking at the other members, she smiles up at Roxas, puzzling him. As Roxas departs for his first training mission, he spots Xion shyly watching him nearby, and Saïx formally introduces her to Axel and Roxas.
When Axel is sent to Castle Oblivion, Xemnas entrusts Roxas with the task of looking after Xion, who quickly bonds with him. After only a couple missions together, Xion removes her hood, surprising Roxas by her gender. She reveals her ability to wield the Keyblade to him, and looks after him when he falls into a coma for several weeks in conjunction to Sora being put to sleep to regain his memories. After discovering that Sora and Riku had slain all of the Organization members (except Axel) that were in Castle Oblivion at the time, Roxas, Axel, and Xion all begin spending more time together as per Roxas's suggestion and become fast friends, such as enjoying sea-salt ice cream together. After Xion asks Axel to be her friend, and he accepts, he stops seeing her as a hooded figure, and begins seeing her as the black-haired girl that Roxas sees.
However, a series of events begin to split the trio apart: While DiZ and Naminé oversee the restoration of the sleeping Sora's memories (moving him from Castle Oblivion to Twilight Town), Roxas begins to experience the process for himself, and begins to ponder over how he is able to wield the Keyblade and doubt the Organization's motives; Axel is reprimanded by their superiors for placing his friendship with Roxas and Xion before the Organization's goals; and Xion is thrown into disarray after a confrontation with Riku, who questions who she is and why she wields the Keyblade; he later finds her unconscious on Destiny Islands, and explains to her that his friend Sora needs Xion to return him his memories if he is to ever awaken. She doesn't understand why she has Sora's memories to begin with, causing her to become torn between staying with her friends in the Organization, or leaving to merge with Sora as Riku suggests.
Xion travels with Riku for several days before being captured by Axel and brought back into the Organization. However Naminé's attempts to restore Sora's memories are soon halted when Xion starts absorbing them faster, causing Roxas to weaken while she becomes stronger, as Xemnas intended. Eventually, after being tricked into fighting Roxas by Saïx, Xion decides to take Riku's advice and leaves the Organization.
After her departure, Xion comes into contact with Naminé in Twilight Town's Old Mansion, questioning her own existence and the fate that will soon befall Roxas. She discovers that she is not a Nobody, but an imperfect Replica of Roxas. Naminé also reveals that as a memory being, once Xion returns to Sora, everyone's memories of her will inevitably be forgotten. Furthermore, Naminé's attempts to restore Sora's memories not only affect Roxas, but Xion as well, stating why they both keep having memory relapses throughout the game. Xion accepts the facts, and decides to go back to Sora. Before she does, though, DiZ barges in with the news that an Organization member has followed her, in which Xion says she will take care of it, despite Naminé's protests, and heads out of the mansion.
It is Axel who has arrived, having finally tracked Xion down. Not only is Axel curious of Xion's motives, he is also given specific orders to capture her again, which would possibly convince Roxas to return to the Organization. Xion refuses, leaving Axel no choice but to accomplish his mission with full force, leading to a heated battle. Having defeated Xion, Axel brings her back to The World That Never Was, but soon faints from fatigue. Xemnas then steps out from the shadows and carries the unconscious Xion away to reprogram her to use the devices he had planted throughout the worlds.
Soon afterward, Roxas finds Xion at the Twilight Town train station, and after she reveals her altered, Sora-like form to him, she explains that she has been compelled by Xemnas to absorb Roxas and become a "full" Sora, which would in turn prevent the real Sora from ever waking. It is explained in her Secret Reports that this is somewhat of a ruse—she knows that Roxas will disappear if she continues to exist, so she plans to force Roxas to absorb her, saving himself and thwarting Xemnas's plan. She then transforms into a monstrous version of Sora using Xemnas's devices, and attacks.
During the battle, Roxas and Xion are transported to Wonderland, Halloween Town, and Agrabah, before returning to Twilight Town. In each world, Xion absorbs power from the "devices" that were placed there, which contain memories of Sora's battles in each world. After a long and grueling battle, Roxas manages to defeat her, while she regains her original appearance in his view. He doesn't seem to recall who she is, though she assures him that he'll be better off now. While Roxas cradles her in his arms, she tells him that she chose to sacrifice herself to slow down Xemnas's plans, asks that he prevent Xemnas from obtaining Kingdom Hearts, and tells him that she is glad that she met him and Axel. As Xion's body crystallizes and disintegrates, Roxas suddenly remembers her name and holds her hand until she disappears completely, leaving behind a single Thalassa Shell.
Though Naminé states that everyone's memories of Xion will vanish as she does, Roxas, Riku, Xemnas, and Saïx manage to retain some memories of her into the next day. By then, Roxas has returned to the World That Never Was in order to set Kingdom Hearts free, which he hopes will reunite him with his lost friend. However, he is being stalked by a swarm of Neoshadow Heartless, as well as a determined Riku, who has arrived to capture Roxas to finish Sora's memory restoration. Riku looks down upon the Nobody as Roxas starts his path up the skyscraper. When Roxas flings his Oblivion Keyblade in an attack on Riku, Xion is able to use it as a medium to beg him to stop Roxas before he can reach Xemnas, because she believes Roxas is not strong enough to face him yet. With the message, Riku recieves memories of the time he spent with Xion, shocking him for a moment, but they begin to fade as he reaches the ground.
When Roxas and Riku finish eradicating the Heartless, they turn on each other for a battle. By this time, it is a struggle for Roxas to even remember Xion's name, and all he knows about her is that he wants her back. While Roxas is able to knock Riku down first, Xion then projects her words to Riku, somehow telepathically, to stop Roxas at any cost, and so he does once he removes his blindfold and transforms into Riku-Ansem. Unconscious, Roxas hears Xion talking to him through his mind, telling him not to be sad, as she has become one with him and Sora, and that soon Roxas will also join them. Despite the fact that memories of Xion have been forgotten by everyone, she tells him that she still has her own memories, so she doesn't mind that he has forgotten her, as she won't forget him or Axel. As Riku knocks him out, Roxas's last memories of Xion fade away.
After Sora catches up to Naminé in his dream in the World that Never Was, she suddenly transforms into Xion. Although Sora doesn't recognize her, he suddenly sheds a tear, to his own surprise and confusion. Xion raises her hood and runs off.
After catching up to Xigbar, Sora comments on how Axel, Roxas, Naminé, and "that other girl" all must have had hearts, saying "You need a heart to cry." When Sora reaffirms to Xigbar that his strength comes from his friends, Xigbar sees an image of the many individuals connected to Sora standing behind him, including Xion. Unnerved, Xigbar leaves Sora to Xemnas and leaves.
After Riku dives into Sora's heart and defeats the Armored Ventus Nightmare, he appears on a memory of the Destiny Islands. After meeting Roxas and Ventus, who each ask him a question, Riku finds Xion sitting on the Paopu tree. She asks him what he wishes, and disappears once he answers. Sora then awakens in the real world.
 Other appearances
After Aqua speaks with Ansem the Wise about Sora, Xion is seen sitting atop the Twilight Town clock tower, eating sea-salt ice cream with Roxas and Axel. Then, Xion and Roxas say Sora's name while watching the sunset together.
 Kingdom Hearts 3D: Dream Drop Distance opening movie
Xion appears during the opening sequence, threatening Roxas with her Kingdom Key as he lands upon a stained glass window. Immediately the scene switches to the three of them—Axel, Roxas, and Xion—messing around, smiling, and eating ice cream atop the Twilight Town clock tower. The scene returns to Xion and Roxas, but Xion disappears in a burst of light, Keyblade and all. Suddenly, Roxas is surrounded by flames, and he pulls out the Oathkeeper and Oblivion, rushing into a battle with Axel.
Xion's Organization coat is similar to the one Roxas wears, with slightly pointed shoulders and closer-fitting sleeves. She also wears the more feminine, heeled boots that Larxene wears and the basic black gloves. Physically, Xion strongly resembles Kairi in her appearance from Kingdom Hearts, having her blue eyes and virtually the same haircut, though Xion's hair is black and her bangs part on a different side. She is slightly shorter than Roxas. As a result of her being crafted from Sora's memories, Xion's appearance is somewhat unstable, as she is known to transform into Roxas (in his Black Cloak) and both Riku and Sora in their original appearances from the first game. Her appearance is also slightly different depending on who is looking at her. Most of the Organization, such as Saïx and, early on, Axel, view her as a hooded puppet, while to Xigbar she appears identical to Ventus. Xemnas, on the other hand, sees her true form—a perfect copy of Sora.
Tomoco Kanemaki is responsible for Xion having black hair.
First arriving at Organization XIII, Xion is a shy, secluded individual. When going on a mission with Roxas, Xion begins to open up to him, and later Axel. She does seem to express emotions due to her nature of existence, and is always happy to be with her friends. However, she is somewhat emotionally fragile, becoming deeply enraged with the right provocation. After finding out the origins of her existence, she also becomes deeply confused and lost. She has a strong sense of justice and generosity, seen in the way she willingly gave up herself to join with Sora. She resembles Kairi and Naminé in the way that she fights to protect those she has come to care for.
Xion seems to take an interest in seashells. While Roxas was in a coma when Sora was put to sleep, Xion placed a seashell on his bedside table every day he was asleep. In her nightmare on Destiny Islands, Roxas is in the dream and picks up a shell while whispering her name. After Xion was absorbed into Roxas, all that was left of her was a single seashell. This is likely a reference to how Kairi also had a liking for seashells.
As an indirect Replica of Sora, Xion's fighting style as a playable character is very similar to his. After absorbing many of Sora's memories using the Organization XIII Devices, Xion is able to replicate Sora's Limits from Kingdom Hearts. However, Xion's movement is quite similar to Limit Form's, jumping back and stepping forward between attacks and slashing through the enemy in the finisher. Like Roxas, she thrusts with one hand and her finisher resembles the Vortex ability. Xion's Limit Break, Event Horizon, involves covering her Keyblade in an aura of Light and performing a devastating combo. Xion can also call down elegantly shaped pillars of light to attack nearby and far away enemies. Before Xion obtains the Keyblade herself, she is limited to simply shooting magic out of her hand, none of which is Light-based.
Once she obtains her Keyblade, Xion proves adept at handling it, being able to fight with it using her right or left hand. Her boss battle depicts her using many powerful melee attacks she seemed to have inherited from Sora. She also uses light much more often during her boss fight, such as creating spiraling circles of Light that suck in the player, leaving them vulnerable to one of Xion's aforementioned physical attacks. She can also use a Light spell similar to Ragnarok, and can envelope her weapon in Light to make her other attacks even more powerful.
Xion's Limit Break in Kingdom Hearts 358/2 Days is Event Horizon (イベントホライズン Ibento Horaizun ). During Event Horizon, Xion rapidly darts around the field with her Keyblade enveloped in light, slashing away at enemies with great strength. In her Final Limit, she summons four thin pillars of light to quickly move in straight paths to ends of the field, dealing heavy damage to any enemies in their path.
As Roxas's Replica, Xion can wield the Keyblade. She wields her weapon fairly skillfully, being able to disarm Axel. Because Xion and Roxas are both part of Sora, they can both wield his Keyblades, even at the same time. Because their weapons are the same, the Gears produce the same forms when applied to either Keyblade.
It is notable that, when Xion runs with her Keyblade, she grasps it with two hands instead of slinging it over her shoulder like Roxas does. This is identical to how Sora runs with his Keyblade in Kingdom Hearts II.
 Notes and references
 See also