User blog comment:Stone Roger/Natsu and Zeref have somekind of relation?/@comment-1359322-20130610122235/@comment-1359322-20130610124131

Hmm, why not that might explain why they were trained by the Dragons and why those Dragon slayers don't have parents. And at least its better than my previous theory of some "mad scientist" dark mage using Zeref's blood/magic/something to create clones of Zeref.