User blog comment:PUNCHURPREGNANT/Gray and Silver Predictions/@comment-190.80.67.66-20140513033951

I personally think that Natsu is Master E.N.D or is connected to him in some way since Igneel wasn't able to kill him (they didn't say he couldn't) because he loved Natsu(E.N.D) so the let him life and tried to mold him into his image. But that's just my theory.