Uh... [The hand goes back to his hair.] We hadn't really... finished things before I ended up here, but... I'm supposed to be some kind of Chosen One, and he was... destined to be killed by me or kill me or... something, I don't know. But he needed to get the Crystal that I get my magic from to get me to come after it, and...

[He gestures vaguely, hopelessly. He has no idea what Ardyn's intentions were, considering the guy is literally insane - and when he was laying out his whole plan, Noct was a little distracted by the fact that he was getting sucked into the Crystal.]

I don't know. He's seriously crazy.