User blog comment:Sargenttacos115/Natsu and Gajeel age Theory/@comment-190.244.6.4-20121204001429/@comment-125.60.156.245-20130831043242

It's not Natsu and Gajeel that were old. I think the reason why they can't pass Freid's barrier is because of their magic. Remember that their magic came from the Dragons from over 400 years ago. Their magic is ancient that's why I think they can't pass the barrier.