User blog comment:HarryS18/ENDs Power/@comment-74.213.97.58-20150823192536

I think E.N.D. curse power is despair, Mard Geer did say they needed a huge amount of despair to wake up END and Zeref mentioned to him that he will give him more despair. Natsu often gives "hope" to his friends which is the opposite of despair and Natsu is the good side while END the evil side, maybe after the book is opened or something the powers sealed inside will return and after he accepts his dark side thus gaining new powers he will be capable of defeating Zeref. But I don't think he will kill him I think the curse on Zeref will be lifted after the battle and disappear.