1. He inherits the Heart of Chaos.
2. This makes him different from everyone else who is experiencing discord and strife.
3. He finds Lightning, can't believe it (Would you?) and sees that it isn't her.
4. They eventually go their own ways to save Serah but in the end they both work together with some others (Snow, etc)
5. Noel marries Lumina. Snow marries Serah. Lightning marries her fist. Vanille marries a now grown up Hope. Fang gets mad at Lightnings fist for taking Lightning away. Nomura finds a way to make that a big story, reminiscent of a Tyler Perry movie.

Thank you. Good bye.
(That last step may or not be a joke.)