This subject was touched upon in another thread, but I wanted to bring it to full light. It's the subject of the relationship between Axel (Kingdom Hearts II) and Reno (Final Fantasy VII), or even if there is a relationship at all. Taking the latter point into account; Tetsuya Nomura may have just designed Axel in reminiscence of Reno because he liked Reno in particular out of his FF creations or maybe he wanted, or maybe Square wanted to add a "Turks" feel to Organization XIII. It's hard to reach a conclusion if we don't know the designer's intentions.
Since "Axel" is an anagram of the original's name with an X, I have surmised that the original person is not Reno. However as stated in the ansem reports: the nobodies have only the slightest variations in their appearance from the originals (this also seems to be true for their heartless forms when comparing Xehanort's heartless (Ansem from the first Kingdom Hearts) with Xehanort and Xemnas). I have therefore concluded that Reno is the heartless that was created from the original body that also belongs to the nobody named Axel. Though one does have to keep in mind the possibility that Axel created an entirely different name for his nobody self (again just like Xehanort and Xemnas), however there is no evidence to support either of these theories.
If I was to incorporate the "Reno is a heartless" theory into the story, it would be this: The latest threat to the Kingdom Hearts universe is the Shin-Ra company. They are an organization of Heartless who want to use the energy of the Hearts of the worlds for whatever reason (It was money in FF7 but that sort of thing seems unimortant in KH), maybe to create an army of powerful heartless SOLDIERs. Whatever it is we learned in KH1 that the heartless are drawn to hearts and the largest heart is the heart of a world. Anyway this is somewhat the same idea as in FF7 when the Shin-Ra used the life energy of the planet to provide energy for the human lifestyle, which would eventually kill the planet. This plot could also be used in KH, replacing the lifestream with the heart of a world. When the Shin-Ra suck up all that energy, the world will disappear. The point I'm trying to make here is that a story where Reno IS a heartless could fit very neatly into Kingdom Hearts.
I'm wondering if Square are already planning this sort of storyline. Please discuss my theory...