User blog comment:Stone Roger/Natsu and Zeref have somekind of relation?/@comment-121.54.32.150-20150427033858/@comment-7418318-20150427071547

At that point of the story Zeref was very unhappy with his life and wanted it to end. But with him being immortal he clearly is having some problems with ending his own life.

For some reason Zeref believed that Natsu would be capable of killing Zeref, so he cried tears of joy about his century-long torment finally coming to an end... though it didn't turn out like that... not yet anyway.

As far as we know Natsu isn't aware of any connection between him and Zeref, though much later in the manga Zeref strongly hinted at him knowing Natsu quite well.

If you only view the anime and aren't reading the manga, I suggest you don't read the following part.