User blog comment:Mode Sau/Strongest Dragon Slayer/@comment-25962249-20150929224240/@comment-1776824-20150930084038

Also, your arguments are based on pure conjecture. We've seen Cobra's cell, and I could argue just as much that he worked out like crazy while in prison. He was already a master of his magic. Just because he can't use magic doesn't mean he can't grow stronger in prison. Look at Natsu; his magic is quite versatile and such, but his real strength comes not from that, but almost literally from his physical prowess. And Wendy has only had about just over a year of training. Cobra had 7 years to peak his body. You said it yourself, she was stuck in stasis...