User blog comment:Stone Roger/Natsu and Zeref have somekind of relation?/@comment-83.81.100.97-20140909165623

Okay so I don't really have a theory but what really is striking, is that in the manga they show all the character like Lucy, Gray, etc with their ages. But they don't know the age of Natsu and Gajeel but they do know the age of Wendy. All dragon slayers. Can someone help me correct me if i'm wrong.