That's right. To save Serah, I'll throw everything else away. I'll even be God's little pawn. No one's going to stop me from trying, not even you. You want to find Yeul? Then find her in death.
Noel Kreiss is a boss in Lightning Returns: Final Fantasy XIII fought at the end of the main quest in Luxerion. If Lightning waits until Day 7 or later to challenge Noel, she will instead be faced with Noel Kreiss+, who has increased stats, dons the Battle Attire DLC costume from Final Fantasy XIII-2, and wields the Endless Paradox.
Noel uses the same fighting style as in Final Fantasy XIII-2; he lands multiple hits with a single attack. Noel is attuned to the Wind element, and thus is vulnerable to Lightning. Noel buffs himself with Haste, Vigilance, Protect, and Shell. When half of his HP has been depleted, he gains access to his Meteor Javelin attack, which deals heavy damage and knocks Lightning into the air when it makes contact with her, rendering her defenseless. If staggered, Noel cannot act; he remains immobile for a short time, but he can be staggered multiple times.
Noel has plenty of HP, and he can be difficult to defeat if Lightning's stats are low. Lightning should be equipped with schemata that possess Thunder-based attacks, such as Sparkstrike. Attack should also be equipped. Deprotect and Deshell can be used to increase the damage Lightning deals to Noel, as well as to nullify the buffs that he casts. Careful timing is needed to guard against Meteor Javelin.