Naminé
Naminé is the Nobody of Kairi,born(along with Roxas) when Sora unlocked unlocked they're hearts with the artificial keyblade. She has the power to change memories. Her first appearance is in Kingdom Hearts: Chain of Memories.
Birth
Naminé was born when Sora had impaled himself with the dark Keyblade forged from the hearts of six of the seven Princesses of Heart (Roxas was born from this process as well) in order to free Kairi's heart from his own. This makes Naminé a very odd Nobody: born from Kairi's heart and Sora's body and soul. Kairi's own body never became a Nobody because her heart lacked darkness, so her body and soul were never able to leave the realm of light. However, this means that Naminé was also born without Kairi's memories, only furthering her status as an unusual entity. She also possesses the ability to manipulate Sora's memories (thanks to the two individuals' close connection), prompting several others, even herself, to call her a "witch".
Castle Oblivion
Naminé, having become a captive of the Organization, resides in the upper floors of Castle Oblivion. When Sora is led into the castle, Naminé is forced by Marluxia and his cohort Larxene to manipulate Sora's memories, slowly causing Sora and his companions to forget many of their friends. At the same time, he is lead to believe that Naminé herself is a very important friend that he had forgotten, though in truth they have never met before. Sora undergoes this manipulation so that Marluxia can have Sora become a puppet under Naminé's control, giving him the strength to overthrow the Superior. Even Kairi is soon forgotten, being replaced by Naminé, and the promise made between Sora and Kairi and lucky charm take on new forms to reflect the replacement. Being motivated by these false memories, Sora continues to ascend Castle Oblivion when he realizes that she is being held against her will by the Organization.
Meanwhile, Naminé is also forced to implant false memories into the Riku Replica, so that he thinks he is the real Riku. However, like Sora, he believes that Naminé is his long lost friend, and that he made the same promise to Naminé that Sora did, and even has an identical lucky charm (though this one is merely a transformed card).
Naminé's conscious eventually allows her to overcome her loneliness and fears, and goes to reveal herself to Sora after being released by the two-faced Axel. She appears to Sora in the memory world version of Destiny Islands as he is conversing with the memory version of Naminé. She tells him that she had never been his heart, despite what his memories show him, and to look for a faint glimmer of light in the deepest regions of his heart, for that light is the person special to him.
Back in the halls of Castle Oblivion, Sora confronts Naminé, realizing that she is not the person special to him.
Just then, the replica arrives, but is defeated. When Sora tries to help, the replica catches Sora off-guard and strikes him, and is about to move in for the finishing blow, but Naminé quickly crushes the replica's memories in his heart, knocking him unconscious. Then, Larxene arrives to finish Sora off but she ends up defeated when she makes the mistake of incurring Sora's wrath by harming Naminé.
After the battle, Naminé explains her actions and motivations, and expresses deep regret, thinking that Sora will not forgive him. Much to her surprise, Sora is completely forgiving, despite the severity of Naminé's doings. When asked if anything can be done to restore their old memories, Naminé says she can do so, but only after they defeat the lord of Castle Oblivion, Marluxia, on the 13th floor. Sora heads off to fight him, and leaves the replica under her care. However, as she is watching over him, Marluxia arrives and kidnaps her.
Marluxia puts her to good use when Axel confronts him about his plot to overthrow the Organization. Marluxia puts up Naminé as a human shield, but Axel is not deterred, saying that he will go through her to defeat him, much to her shock. Of course, she is saved by the timely intervention of Sora, though he fails to stop Marluxia from escaping with Naminé. Nonetheless, Sora defeats Axel and moves on to Marluxia, who orders Naminé to sever the chains of memories in Sora's heart, seeing that in his current state, he is of no use to him. But even so, Marluxia can eventually restore Sora and make him his puppet. However, Naminé refuses the order, and Marluxia threatens to kill her, but in the end, she is saved by the Riku Replica's arrival. Sora, Donald, and Goofy then initiate one final battle as the replica guards Naminé.
After Marluxia is defeated and the replica departs, Naminé presents Sora with the choice of either remembering the events of Castle Oblivion and abandon his old memories, or regain those and lose the ones of Castle Oblivion. She understands his choice of the latter, and leads Sora, Donald, and Goofy to a chamber housing crystal pods. In these, they can sleep while Naminé works to restore their memories. Though it will take some time, she assures him that he will eventually become his former self. However, Sora believes that Naminé will always be in his heart, forgotten but not lost. Thus, the two promise to meet again as real friends, just before Sora falls into a deep slumber.
Reverse Rebirth
Naminé also aids Riku in his efforts to conquer the darkness within him. When Zexion overwhelms him with light, Naminé takes on Kairi's form to convince him that he should accept the darkness as well as the light. Thus, he is given the strength to move through the light and strike down Zexion, who only just barely escapes.
Naminé and Riku meet again later at the urging of DiZ and she reveals Sora to him, who has fallen into a deep slumber in order to have his memories restored. She offers Riku to seal away the darkness in his heart, though he too would have to sleep like Sora. But Riku ultimately chooses to face the darkness on his own, and Naminé sees that he has made the right choice. He also reveals his suspicion that it was Naminé who appeared to him as Kairi, which she confirms, although she is surprised. Riku notes that the two "smell the same", before going off to face his darkness.
A Year Later
Naminé again appears in Kingdom Hearts II, working with DiZ and Riku (who has taken on the appearance of Xehanort's Heartless in order to use the darkness) to restore Sora's memories. Because Sora is incomplete, Naminé is having difficulty chaining back Sora's memories, so his Nobody, Roxas, is retrieved and placed into a digital Twilight Town, where he will live out his days until the time came for him to join with Sora.
However, despite her promise too help Sora, she begins too feel a bond towards Roxas, noticing they are both being used(by the Organization and DiZ) because of being born special. Eventually, she starts acting on her own(not on Diz' approval) and tries too save Roxas, or at least help him before his fusion. In the novel, she talks with Axel on the rooftop and he says "Only you can save him, got it memorized?" and leaves before Namine can reply.
However, Naminé begins acting out, and contacts Roxas, nearly revealing the truth to him, but is stopped in the nick of time by Riku(still guised as Xenahorts Heartless). Still, their encounter gives Roxas an opportunity to meet with Kairi.
The two meet again soon after, and this time, Naminé manages to reveals Roxas' status as a Nobody. Upon seeing Roxas' reaction to the revelation, she apologizes and remarks that "some things really are better left unsaid".
On the final day of Roxas' time as an independent entity, they meet once more, and Naminé sheds light on Organization XIII, and their search for Kingdom Hearts. However, this Naminé is made from data, and is deleted before she can speak any further. But the true Naminé appears, telling Roxas that he will not disappear when he fuses with Sora, and will instead be whole. DiZ quickly tries to stop her, but before she is taken away, she promises him that they will meet again, even if they don't recognize each other.
The World That Never Was
Naminé makes her final appearance in the game's last world, The World That Never Was. She breaks into the Organization's stronghold, rescuing Pluto and Kairi from their cell in the Organization's dungeon. They then proceed to find Sora, though Naminé's close proximity to her counterpart causes her to blink in and out of existence.
While searching for Sora, they are intercepted by Saïx. However, Riku arrives on the scene, and manages to drive off Saïx. Naminé then tells him that he can take over from this point.
After the first battle with the Kingdom Hearts powered Xemnas, Naminé appears another time, projecting herself from Kairi, and opens up a pathway to Destiny Islands. Kairi thanks her for the help. Naminé then tells Sora that they meet again, though he does not understand what she means. At that moment, Roxas projects herself from Sora, and the two Nobodies are glad to meet once more, just as Naminé promised. The two realize that not all Nobodies are doomed to fade into the darkness, as they were able to meet their original selves, and though they are no longer independent, they will still live on through Sora and Kairi. And without regret, the two rejoin with Sora and Kairi once more.
The two are last scene in the ending FMV, when Sora and Riku return home to a waiting Kairi. As Sora and Kairi smile at each other, so do Roxas and Naminé.
Memory Manipulation
Unlike other humanoid Nobodies, Naminé's talents do not lie in battle, but in the ability to control memories, making her a "witch". The ability comes from the fact that she is formed from Sora's soul and body, rather than Kairi's. Because of this connection, Naminé can move around the "links", his memories, that are located within his heart to her liking, as well as the ones of those who are connected to Sora. She can even sever them completely, turning the victim into little more than an empty shell.
However, as she is Kairi's Nobody, it is impossible for Naminé to completely snuff out Kairi from anyone's memories. On the other hand, those with the greatest connections to Sora cannot ever completely forget him, as evidenced by Kairi.
Naminé also has another limitation to her power. When Naminé took on the task of re-chaining Sora's memories so that he will remember everything he had forgotten, but lose his memories of Castle Oblivion, she was unable to make much progress. DiZ reasons that it must be because Sora's other half, Roxas, is missing, and in order to restore Sora, Roxas must become one with Sora. Thus, linking memories back together is a far more difficult and elaborate task than breaking them.
How Naminé actually manipulates memories is something to be noted. As she is always drawing pictures on her sketchpad, DiZ believes that she draws in order to capture the memories she needs to chain together. Because of this, the walls of her room are covered by pictures of events, places, and people that are in Sora's memory.
