Quote Originally Posted by Saphyrrion Wisdom
In the beginning of the game,I played ofcourse with Roxas,and I think that he's the bigshot,and not Sora...I mean,he's so cool.I don't know what happened with him,co'z I didn't beat the game yet.I just do not have ebough time for it...Unfortunately....
You simply have to get further in the game. Anything else is a Spoiler. I'm sure you'll find the time.

(SPOILER)If you haven't already figured it out, then I pity you.

Anyways, Roxas is Sora's Nobody, as is evidenced in KHI, and scenes in KHII. They are together, but not in the sense of one cooperating with the other. However, this changes at Memory Skyscraper, when Sora and Roxas duel each other in a cutscene, and Roxas recognizes that Sora is a "good other". After this, you can begin to try to trigger the Final Form, the uber-newber pwnage.