Namine is technically Sora's second Nobody, but created from Kairi's heart. It just depends on the way you look at it.

Uhm, alright, here's a question I've adressed once in KH13's forums; a forum which by the way is only filled with little rascals, so that the thread sorta consisted of stupid, not-sense-making answers, so here's the question..- Oh yeah, Birth by Sleep spoilers possible, so watch out:

Xion is an abortive replica of Sora. She essentially is made up from his memories. This brought about the fact everybody seeing her 'differently', or more specific: their 'Xion' depends on their memories.

According to KH's 'memory-system', some of Ventus's memories -which were put into Sora's heart in BBS- also got into Xion, what -besides of what I've mentioned above- caused her to look like Ven when she battles Xigbar.

Here's the question: Why didn't everybody else, especially Axel, who'd definitely met Ven, see her as Ven?