Naminé was born when Sora
released the heart of Kairi
from his body (as well as his own) near the end of Kingdom Hearts, being the entity of Kairi's heart and Sora's body. This made 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 and thus made it seem like Kairi was in a comatose state until she regained her heart. However, this means that Naminé was also born without Kairi's memories, only furthering her status as an unusual entity. And because of the fact that Naminé is formed from Sora's body, she has the power to manipulate his memories as well as the memories of those who are connected to him, prompting several others, even herself, to call her a "witch". She was brought to Castle Oblivion against her will, being held by Marluxia
, member of Organization XIII
Naminé spends her time in the white Castle by drawing Sora`s memories and beloved ones.
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 led to believe that Naminé herself is a very important friend that he had forgotten, though in truth they had 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.
Naminé`s loneliness and jelousy grew inside her, knowing Sora with a good heart and that he cared so deeply for Kairi, she removed Kairi from his, although she even was forced too.
Even Kairi is soon forgotten, being replaced by Naminé, and the promise made between Sora and Kairi and her lucky charm take on new forms to reflect the replacement. Being motivated by these false memories, Sora thinks Naminé is her lost friend and when he knows she is against her will in the Castle, Sora soonly tries to save her, ascending deeper to the Castle, not knowing she was saving the girl lying to him through his memories.
Larxene, Marluxia`a partner were trying to overthrow Organization XIII and using Naminé. Laxene forces Nasminé to make false memories on the Riku Replica is also forced to implant false memories, thinking he was the real Riku. She gaves him the memory of Riku and herself (Naminé) sitting on the beach one night, when suddenly a meteorite shower arrives and he swores to protect her. While she was implanting those fake memories on the Riku Replica, she was also making false memories on Sora, making this too real to deny.
For a moment, it is shown in his memories he is on the beach in night, and he sees Naminé. He runs to her and Naminé shows sad (feeling uncomfortable about lying to such a gentle boy) and Sora shows her his lucky charm that it is suppossed to look the same as the one that Kairi made for him although its a transformed card.
Naminé walks around the Castle, when Axel appears and convinces her to do the right thing for Sora. Naminé nods and she runs for telling Sora the truth.
Sora finally sees Naminé and she tells him the truth saying dispite his memories shows him she is the special girl, she isn`t. Sora, really furios confronts her , realizing that she is not the person special to him. Just then, the replica arrives, but is defeated. When Sora tries to help him, 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. Sora, thinking that the replica was the real Riku, starts worrying and telling Naminé what she has done; Larxene arrives and tells Sora all about what has Naminé done and also telling him that the replica wasn´t the real Riku. Sora lying on the floor starts to be confused, but he was a bit harmed so Larxene takes advantage and approaches. Naminé runs and stands in the way, but Larxene starts telling her a traitor and she punches her, leaving Naminé unconcious on the floor. Sora shouts for her and Larxene wonders telling Sora why is he worried, that she lied to him but Sora said that he still made a promise to her and battles Larxene, defeating her.
After the battle, Naminé explains her actions and motivations, and expresses deep regret, thinking that Sora will not forgive her. 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 Organization XIII. 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 keeping his memories of the events that took place in Castle Oblivion and abandoning his old memories, or regain those and lose the ones of Castle Oblivion. Sora really wants to regain his lost memories, but he doesn`t want to forget a good freind, Naminé. He tells Naminé he wants his old memories and Naminé understands his choice, telling him that who would like fake memories. She shows the way to Sora, Donald, and Goofy to a chamber housing crystal pods. In these, they can sleep while Naminé works to restore their memories. Sora and Naminé say goodbye to each other, but Naminé tells him that they would meet again, although Sora doesn`t recognize her; and they promise to each other. 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. Sora says goodbye and Naminé feeling she has done something good at last, makes Sora into a deep sleep that will last for one year (Donald and Goofy too).
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.
Kingdom Hearts II
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 power of 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 by Riku 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, Naminé desires to see Roxas, having developed a connection with him, and thus enters herself into the digital Twilight Town. There, she meets Roxas, and acts as a guide toward Roxas when he is attacked by Nobodies. After Roxas' Dive into the Heart, Naminé meets with Roxas again, saving him from the darkness that bursts forth from the Twilight Town. She plans to reveal the truth of who Roxas is to him, but is stopped by Riku before she can do so. Even so, their encounter puts Roxas into contact with Kairi the next day.
On the day following, Roxas enters the mansion were Naminé was. Naminé notices her drawings in the wall capted his attention, specially his drawing with Sora (Roxas has seen him in his dreams). Naminé lets him know she was present. They both started to have a nice conversation, but Naminé gave too much information. She told him his origin about being a nobody and she revealed her nobody entity too. His friendship with Axel and also mentioned everything about Sora. Roxas' reaction wasn´t qiute the reaction Naminé expected, 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.
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 Kairi that he can take over from this point, and vanishes.
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 himself 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, Naminé finally joins with Kairi.
The two are last seen in the ending FMV, when Sora and Riku return home to a waiting Kairi. As Sora looks up to smile at Kairi, he takes the appearance of Roxas. Kairi then takes on the appearance of Naminé, smiling back.
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. She can even create objects affected by the new memories, evidenced by turning a card into a good luck charm for the Riku Replica.
However, as she is Kairi's Nobody, it is impossible for Naminé to completely snuff out Kairi from anyone's memories. Conversely, 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. Several of them are also of Roxas, implying her ability to fiddle with Roxas' memories as well.