User blog comment:Natsu11/Zeref and Natsu?/@comment-189.121.51.191-20130922001133

Based into everything you said I can tell my own theory based in everyone's theories over here, I don't have a concrete relationship between Zeref and Natsu because they can be brothers or even father and son. My theory is that Natsu on an alternative dimension when the first attack of the dragons finished(Lucy from the future says that the dragons entered the portal and attack, so maybe Natsu used the portal at the same time to meet Igneel) so 400 years ago Natsu could meet Zeref as the dark magician and after this Zeref would change as someone that appreciattes the life but as time passes Zeref don't dies and Natsu gets old and dies telling him that he might be able to help him finish with his misery(eternal life and rejection of the world) on the future (when they finally met at the island where the test was taking place and the young natsu attacks not hurting him at all he feels sad because he knows that natsu is not strong enough). Maybe the dragons that disappeared because they are on a different dimension where they are able to see everything(several chapters you can notice that igneel is watching natsu and supporting him) and on one chapter Wendy's sky dragon talks to Igneel that Natsu could met wendy and that she hoped they could met nicely(Proof that maybe on other dimension Natsu and Wendy fight or are enemies). Also the relationship between Zeref and Marvis could be they used to be a couple but somehow marvis got killed by acnologia(that's why zeref gets mad when the second master "invocates" Acnologia at the island where that S class was being taken by fairy tail members). Since Zeref used to be evil maybe he managed to make one spell to live forever but the cost was that world would be rejecting him, that's why after his convertion he could not break the spell and continues living into misery.