Within Kingdom Hearts II is the story of Cloud and the battle he faces with his own darkness. Much about his struggle is left unclear, and this story is a completely optional aspect of the game, not being necessary to beat the game.
Related ThreadsThe Kingdom Hearts story - last post by @ Dec 21, 2002
What about Leon and Cloud? - last post by @ Feb 12, 2007
kingdom hearts story 2 ch 1 - last post by @ Mar 4, 2008
Continue This Story ver.2 - last post by @ Feb 12, 2003