User blog comment:IamJakuhoRaikoben/Chapter 445: The Ugly Fairy, Review./@comment-24228963-20150718064255/@comment-1153699-20150718195425

The CSK is nothing compared to someone who can at least give Zeref a run for his money tbh but she might stand a chance with the other two power ups.

I think Natsu is the one who will defeat E.N.D. Hiro (somewhat) foreshadowed this when he made Zeref say "You just might be able to" when Natsu said he's gonna beat E.N.D..