User blog comment:Stone Roger/Natsu and Zeref have somekind of relation?/@comment-2.49.84.79-20140225050107

I don't think they have any relationship, zeref right now feels like he has to die to atone for his sins so he just foresees that natsu one day can make it happen. That's the only reason why zeref knows natsu. He is a dragon slayer with the potential to kill an immortal.