User blog comment:Besteverunited/Do you guys think that Natsu is the only demon Zeref created or do you think the other dragon slayers were created by him to?/@comment-24784846-20150518221531/@comment-5894890-20150518225852

Oh right! that age thing back from the festival :o. Acnologia having a kid is weird to me though o_o, other than what Godisme pointed out, I don't think Acnologia would have a lover? it just seems weird. I'm just going to take a guess that Gajeel is a failed demon (1st test subject) compared to Natsu :P. OR all demon slayers are somehow related to Zeref, and how they're a test subject of sorts, because all of them don't have human-parent stories anyways.