He never sees Kairi in his dreams; it seems almost cruel. Nomatter how deep he dives inside himself he can never meet her there — he can never meet her because she's the only person who cannot exist there. If Sora contains a complete universe of interconnected worlds and peoples, Kairi contains another — one wholly disconnected and apart from his own, beautiful and unknowable. She is the one he is always searching for, reaching his fingers out across a vast chasm of time and oceans, earth and sky. He knows that she is reaching back, across the same sky, to him.
When this is over he knows that they will be together again; then they can lie in the sun together and at last he will explore her universe, and she will explore his. Until then the sun sets daily out of his sky and into her ocean like a shimmering golden missive between worlds. He would like to bottle a message up inside the sun for her — a single shining word: "Soon." I promise, soon.
He would like to go back to her now; he would like to run his fingers through her hair, split a paopu with her, and kiss her eyelashes. He would like to tell her that it was all for her, right from the first moment: it was her that he wanted to run away with, it was her that he battled his way across worlds for — right to the heart of all worlds. He saved the world for her, kept it warm and beautiful for her. He loved the world, loved every aspect of the world. And he did it for the world. But more than anything else he loved her. And he did it for her.
He never sees her in his dreams; some days she's all he wants to see. He needs her because she is the only one he can never see there. He needs her because she is everything he can never be. He needs her because he can never swallow her up into him, just as she can never swallow him up into her.
If she had been anyone else maybe Xion would have been complete. He wishes he could have given completion to her; it seems too sad that she and Roxas are trapped within him now forever, suspended in the vast open sky of his heart. Once he took it to pieces to wake Kairi from slumber — and Roxas was born whole from within him, his love for Kairi given voice and form and heart. Roxas appears in a lot of Sora's dreams, golden and smiling. Xion is always a little sad. Sora cannot give them what he once gave Kairi. He cannot dismantle his heart for anyone but her.
He stretches out on the silver, sandy beach between worlds. The ocean sings him a gentle lullaby, soft and sweet; above him the sky twists and gleams. He knows she won't — can't — be there when he closes his eyes. But he smiles anyway. The sea touches the sky along all its edges — and in some way he knows that they are still together.