User blog comment:Sargenttacos115/Natsu and Gajeel age Theory/@comment-36.76.57.74-20140801114524

Why natsu and gajeel can't pass the runes, I think it's just one of mashima's jokes. I once read that mashima wrote this manga basically just for laugh and so if the jokes get good response, he can write one arc about it. Anyway it's just my opinion.