What exactly is Namine? This has been a question since KH2 brought to attention that she is Kairi's Nobody but lacking all the "necessary" parts. As funny as it is, the answer has been right in front of our noses the entire time. Yep, we've had the answer to that question ever since it's birth, what is it? Well, let's first look at what a nobody is...
If a person with a strong enough heart loses their heart to darkness, the body left without a heart will then become reconstructed as a Nobody. An interesting thing to note is how exceptionally strong hearts will leave exceptionally strong imprints on their bodies before being completely lost to the darkness. Got it memorized? Good, let's continue. Hearts have this funny way of changing the appearance of bodies that they are in. Examples? Ansem SoD inside Riku's body, Ventus's heart inside Sora's Nobody, and The pieces of Xehanort's heart inside his vessels.
Now, remember how in KH1 Sora lost his body, became a heartless, then got a new body from Kairi? Well that body that Sora got wasn't an actual body, it was a PPS created mostly from Kairi's Princess Magic... Get where I'm going with this yet?
When Sora used Ansem's artificial keyblade on himself, it released Sora and Kairi's hearts from Sora's body. This simple process is what created Roxas and Naminé. Roxas took with him Sora's body/soul and Ventus's heart while what Naminé took was a bit more ambiguous. Through the subconscious use of her Princess Magic (or the forced use of thanks to the effects of the PoH Keyblade), Kairi created yet another (or her first if you're looking at it chronologically) Psuedo body made of light. However, it didn't finish forming until about the same time as Roxas.
While the imprints that Kairi left were the strongest, Naminé isn't without influence from other hearts. Naminé also recieved subtle influences from Sora (being connected to his memories) and Ventus (Blonde Hair, I'd also venture to say that Ventus's influences are why she showed up in Castle Oblivion).
Alright, let's summarize; Naminé is the Nobody of Kairi, however unlike most Nobodies, her "body" isn't actually a body as it's really a Psuedo body made from Princess Magics. This "Pseudo Body" went through the same process all Nobodies go through, but received some extra imprints from hearts other than Kairi's. These added imprints subtly changed Naminé causing her to look slightly different than Kairi.
... and that's pretty much it, if you have any questions, feel free to ask
If a person with a strong enough heart loses their heart to darkness, the body left without a heart will then become reconstructed as a Nobody. An interesting thing to note is how exceptionally strong hearts will leave exceptionally strong imprints on their bodies before being completely lost to the darkness. Got it memorized? Good, let's continue. Hearts have this funny way of changing the appearance of bodies that they are in. Examples? Ansem SoD inside Riku's body, Ventus's heart inside Sora's Nobody, and The pieces of Xehanort's heart inside his vessels.
Now, remember how in KH1 Sora lost his body, became a heartless, then got a new body from Kairi? Well that body that Sora got wasn't an actual body, it was a PPS created mostly from Kairi's Princess Magic... Get where I'm going with this yet?
When Sora used Ansem's artificial keyblade on himself, it released Sora and Kairi's hearts from Sora's body. This simple process is what created Roxas and Naminé. Roxas took with him Sora's body/soul and Ventus's heart while what Naminé took was a bit more ambiguous. Through the subconscious use of her Princess Magic (or the forced use of thanks to the effects of the PoH Keyblade), Kairi created yet another (or her first if you're looking at it chronologically) Psuedo body made of light. However, it didn't finish forming until about the same time as Roxas.
While the imprints that Kairi left were the strongest, Naminé isn't without influence from other hearts. Naminé also recieved subtle influences from Sora (being connected to his memories) and Ventus (Blonde Hair, I'd also venture to say that Ventus's influences are why she showed up in Castle Oblivion).
Alright, let's summarize; Naminé is the Nobody of Kairi, however unlike most Nobodies, her "body" isn't actually a body as it's really a Psuedo body made from Princess Magics. This "Pseudo Body" went through the same process all Nobodies go through, but received some extra imprints from hearts other than Kairi's. These added imprints subtly changed Naminé causing her to look slightly different than Kairi.
... and that's pretty much it, if you have any questions, feel free to ask