User blog comment:Miskos3/Fairy Tail 520: Dragon or Demon, Review/@comment-29874610-20170204151505/@comment-1776824-20170204202907

Natsu has a human body, so of course he would be spoken of as being a human. However, the fact that the demon seed existed inside of him made him an Etherious. It is not tethered to his life, but is, as was said, the "proof that Natsu['s true identity] is [that of] END." He also definitely had access to a demon's power; look at Gray vs. Natsu. That was one of your entire arguments for months: Natsu having demon power. The seed is not that which brought Natsu back to life, but is rather the proof that he was indeed brought back to life at some point. Its destruction means that his life and Zeref's life are no longer tethered. That's the bottom line. It makes absolute perfect sense, despite the lackluster resolution.