Quote Originally Posted by Loony BoB View Post
He was searching for the love of his life's sibling because it was important to the love of his life. Then he found out that he had to save the world. I would say that "the world" probably also includes the love of his life. Basically, if he wasn't in love with Serah, I highly doubt he would have been looking for Lightning.
If you just got back with the one you love, would you really leave without her, why not take her with you?