User blog comment:Stone Roger/Natsu and Zeref have somekind of relation?/@comment-101.174.197.171-20140430072854

I wonder if Zeref was actually in Edolas for some time and he knew Edolas version Natsu but had no idea he was in another world for some time, that way he does know Natsu in some way, but Earthland Natsu does not know him.