User blog comment:FairyRaven/Fairy Tail Chapter 394: Juvia vs. Keith, Review and Commentary/@comment-24066070-20140726014456

Since "Natsu is E.N.D." has become more likely since the revelation that E.N.D. is a Fire Demon, I'd like to discuss another possible clue.

Namely Silver's reaction (and apparent disgust) towards Natsu after giving the blanket to Lisanna.

Perhaps Silver knew more about Natsu's origin or the plans Marde might have with him.