User blog comment:Stone Roger/Natsu and Zeref have somekind of relation?/@comment-115.186.111.149-20140828103805

It's possible that Zeref could be related to natsu with the way he looked at him when seeing him all grown up. And in the manga he also said to natsu ,when again meeting him that either natsu or E.N.D would reach him. And that also igneel could not kill E.N.D. This implies that E.N.D also has some relation to Natsu. My guess is that E.N.D could be Natsus brother and Zeref could be Natsus biological father who might have abandoned him while he was young and igneel might have found him and taken care of him... Even I could be wrong, this is just my speculation...