User blog comment:IamJakuhoRaikoben/Chapter 373: Life or Death?, Review./@comment-5840892-20140228175138/@comment-24066070-20140301203136

Or E.N.D. is the Dragon Slayer student of Acnologia or one of Acnologia's alles when Acno was still human (Zeref turned one into a Dragon and the other into a Demon)