Xion

Xion is the fourteenth member of Organization XIII, first appearing in the game Kingdom Hearts 358/2 Days. She is not actually a Nobody, and not even a true member of the Organization. Instead, she's an imperfect Replica of Sora created from his leaked memories by Xemnas as a fail-safe in case Sora proved to be useless to Organization XIII's plans. This, in consequence, slows 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 and component 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. Those with connections to Sora view her as Xion (and later, as Sora), while Xemnas and Xigbar see her as Ventus, and Saïx only sees a hooded doll.

Like Sora and Roxas, Xion can wield a Keyblade, the Kingdom Key, leading to a brief confrontation with Riku who questions why she can wield the Keyblade, and whether or not it is real.

In keeping with water-related names of Kairi, Naminé, and Aqua, Xion's name contains shio (潮), meaning "tide".

Kingdom Hearts 358/2 Days
When Axel is sent to Castle Oblivion, Xemnas entrusts Roxas to look after Xion, who quickly bonds with him. She reveals her ability to wield the Keyblade to him, and looks after him after he falls into a coma for several weeks in conjunction to Sora being put to sleep to regain his memories. After discovering that all Organization members in Castle Oblivion except Axel have been slain by Sora and Riku, Roxas, Axel, and Xion all begin spending more time together as per Roxas's suggestion and become fast friends, resembling in some points Riku, Sora, and Kairi.

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, becoming torn between staying with her friends and leaving the Organization to merge with her true self as Riku suggests. Eventually, Xion chooses to leave the Organization; when Roxas and Axel attempt to stop her, she gets in a physical fight with Axel that a horrified Roxas tries in vain to prevent.



After her departure, Xion discovers that she is not a Nobody, but an imperfect Replica of Sora created from his leaked memories by Xemnas as a fail-safe in case Sora turned out to be useless to the Organization's plans; the reason she resembles Kairi is because of Sora's strong feelings for her. In addition, Naminé's attempts to restore Sora's memories not only affect Roxas, but Xion as well, to the point where she begins to take on Sora's physical appearance. Unable to cope with this revelation, Xion falls into a deep depression and begins to fall apart mentally.

Xion comes into contact with Namine at the Old Mansion, questioning her own existence and the fate that will soon befall Roxas. Axel arrives shortly afterwards, having finally tracked Xion down. Not only is Axel curious of Xion's motives, he is also obsessed with trying to capture Xion again, in order for 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 Castle Oblivion, soon after fainting from fatigue. Xemnas then steps out from the shadows and carries the unconsious Xion away, leaving her fate unknown.



Soon after, Xion, now completely insane and perfectly resembling Sora, confronts Roxas at the Twilight Town train station, and after revealing her altered form to him, transforms into an armored creature and attacks him, planning to kill and absorb Roxas in a delusional attempt to become a real person, uncaring that this would prevent the real Sora from ever awakening. After a grueling battle, Roxas defeats the deranged clone of his former self, who regains both her sanity and her original appearance. Cradling Xion in his arms, Roxas shares an emotional conversation with her, during which she explains to him that she had no regrets for meeting him or Axel, reveals the true colors of the Organization to him, and pleads with him not to let Xemnas win before dying peacefully in his arms. Emotionally shattered, Roxas absorbs Xion's degenerating body (taking in Sora's memories), the energy granting him the use of her Keyblade (allowing him to dual-wield both his and hers as well) in addition to inadvertently bringing the restoration of Sora's memories to a complete stop.

In the Secret Reports obtained at the end of the game, it is revealed that she is experiment "No.i" of the Replica Project, and that she was bestowed a proper name, Xion, because living things need names to give meaning to their existence, and being a member of the Organization.

Moments before the end of the game, Riku and Roxas are engaged in a battle, and it seems Riku has flashbacks of meeting Xion at Beast's Castle and Destiny Islands, which repeats a few times throughout the battle, but each time it happens the scenes start to become blurry as though the memories of Xion -- Replica No.i -- fade away like they weren't real. It has been said that Naminé was the one who did this, which would also explain why she was never mentioned in Kingdom Hearts II as everyone just seemed to forget about her. Also, during the battle Xion speaks to Riku at some point, telling him to stop Roxas. After Riku manages to stop Roxas, Xion talks to Roxas through his mind, telling him not to be sad because she has become one with him and Sora, then she tells him that soon he too will become one with Sora, so basically she will still be with him, as both of them are connected to Sora. Despite the fact the memories of Xion have been forgotten by everyone, she tells him that she still has her memories, so she doesn't mind that he has forgotten about her, as she won't forget him or Axel.

Personality
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. While she may seem monotone, she does 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.

Fighting Style
As a replica of Sora, she can wield the Keyblade and her fighting style greatly resembles his original Kingdom Hearts incarnation. However her style is more similar to Roxas. Like Roxas she thrusts with one hand and her finisher resembles the Vortex ability. The two can apparently share keychains with each other, allowing them to use the same Keyblades. In multiplayer, they also have the same limit break, Event Horizon. Xion appears somewhat vulnerable to attacks, as she is easily rendered unconscious after Axel smacks her upside the head, and is swiftly knocked to the ground in one blow to the back from Riku. Before Xion obtains a Keyblade of her own, she is limited to simply shooting magic out of her hand. Another similarity to Roxas is they both share the same attribute, Light. Xion's essence lives on in Roxas after being absorbed, as the process allowed him to dual-wield his and her Keyblades.

Quotes
"Is it that I'm not supposed to exist?"

"I want...I wanna be...With you two..."

"I can't, not the way I am now."

"What would it take for me to be like you?"

"So, do you hate me for taking your friend away from you?"

"You have poured so many memories into me. Given me so much, that I feel like I'm about to over flow. Look at me, Roxas. Who do you see?"

"Don't hold back..... Axel" 

"This is Sora"

"No.... I'm disappearing because I want to. I won't let Xemnas have his way."

Trivia

 * During Xion's battles, Roxas is transported to Wonderland, Halloween Town, Agrabah, and finally Twilight Town. It is unknown why Xion does this, though this is most likely a side effect of having Sora's memories, as said person has visited these worlds before, with the exception of the real Twilight Town, although Sora visited a memory-generated Twilight Town in Kingdom Hearts: Chain of Memories.


 * When Xion takes the physical appearance of Sora, her Organization garments turn into a male equivalent (very similar to Roxas) which may imply that her entire body is the same as Sora's; however, her voice is still the same.


 * During her nightmare at Destiny Islands, Xion recalls not Sora's but Riku's memories of his confrontation with Zexion, something Sora never had the knowledge of. It is possible that some of the leaked memories that created Xion came also from Riku, however, that is never revealed.


 * During a scene where Xigbar is about to battle Xion in Wonderland, he sees her appearance as Ven, which distracts him, allowing her to knock him to the ground. This is likely due to the fact that she is made of Sora's memories, and emitted Xigbar's memories of Ven, but Ven's connection to Sora remains unknown.


 * When listening to Xion's theme, parts of Kairi's theme can be heard in certain parts, further emphasizing their memory based connection to one another.