Description

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 the first game, having virtually the same haircut (though Xion's hair is black and parted on the left side of her head rather than the right as it was on Kairi) and eye color (blue). She is roughly the same height as Roxas, albeit a bit shorter. As a result of her being crafted from Sora's memories, Xion's appearance is somewhat unstable and she transforms 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, which is most noticeable when Xigbar sees her as Ventus.

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. 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 Namine 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 put 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.

Equipment

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 Keyblade, even at the same time. Xion and Roxas can share Keychains with each other, allowing them to use the same Keyblades and limit break in multiplayer mode.
It is notable that, when Xion runs with her Keyblade, she grasps it with two hands instead of slinging it over her shoulder. This is similar if not identical to how Sora runs with his keyblade in Kingdom Hearts II.

History

Xion is the fourteenth member of Organization XIII, first appearing in the game Kingdom Hearts 358/2 Days, in which she could be viewed as both a protagonist and antagonist. She is not actually a Nobody, and is not even a true 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's 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), while Xemnas and Xigbar see her as Ventus, and Saïx 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 contains the Japanese words for "tide" (潮 shio?), fitting the oceanic naming theme of Kairi and Naminé, and Aster tataricus (紫苑 shion?). According to Japanese floriography, Aster tataricus is used to mean "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.