roxas was always soras nobody, and he formed when sora became a heartless, because sora's heart was so strong, roxas was formed and then joined organization XIII and supposedly there was a 14th member of organization 13 so basicaly in 358/2 days its organization 14 then 13. sorry if i spoiled 358/ 2 a little.
That's because in Kingdom Hearts 1 when Sora turns the keyblade on himself he turns into a heartless and that created Roxas as Sora's Nobody. Roxas became a part of the Organization of Nobodies Organization VIII and that's what brought the organization into Kingdom Hearts at all. But it was at the End of Kingdom Hearts so they put the organization in Kingdom Hearts Chain of Memories and Kingdom Hearts 2.
Sora killed himself in the first Kingdom Hearts that came out.
they're hearts will be complete
roxas is the nobody of sora, originated after sora released his heart in Kingdom Hearts I
Roxas is Sora's Nobody.
Lea
He is a nobody. As a matter of fact, he is Sora's nobody.
They're two different people. Roxas, Sora's Nobody, is blonde. Sora is a brunette.
Saix is the nobody to Isa. He and Axel's original, Lea, are first seen in Kingdom Hearts, Birth By Sleep. He was not someone already known through out the previous games.
Xemnas does not exist in Kingdom Hearts 1, but he is the leader of Organization 13 because of Ansem in Kingodm Hearts 1. Xemnas is a nobody so there for he does not exist without someone to live by that was once part of the darkness. Therefore when Riku became part of Ansem in the Darkness Xemnas was born a nobody. Also when Sora became a shadow to save Kairi's heart Roxas was born therefore the keybearer for Organization 13.
Nobody knows yet
Nobody really knows. If your talking about Kingdom Hearts Birth By Sleep, then you should know that that isn't Kingdom Hearts 3. You're just going to have to wait until the game comes out.