One of the most powerful things about this scene is how little Sora knows and how much Roxas knows.
Sora glares at his unbeknownst enemy, doubtful and confused as to who this boy is, and why he is fighting with him.
Roxas looks upward, bracing himself for what he has to do. He now knows of all that has been his existence- his days with the organization, his days in the fake Twilight Town, his struggles with Axel, and his nature as a Nobody who must now do what is “right”- even though what is “right” requires him to lose himself and succumb to the identity of Sora, his Somebody. Roxas finally has a full picture of his “life”, memories, and role in this struggle to subdue the darkness. And here, in this, he takes comfort in the fact that his Somebody is someone worth sacrificing himself for. He takes a breath, and straightens himself up, preparing for what is about to happen and telling himself that it will be okay, that he is okay with this.
And Sora doesn’t see any of it.