User blog comment:GotMilk5101520/How will the Tartarus Arc Part 4 will end?/@comment-5303512-20140709034950/@comment-7418318-20140709085208

Or come to think of it, Igneel might have destroyed only the body of E.N.D. and thanks to the other Demons reviving we know that this isn't enough to kill them for good.

If Zeref meant that, he chose a very odd way to express himself, but then he's from 400 years ago and not the most conventional character to begin with.