User blog comment:Miskos3/Fairy Tail Chapter 320: Roaring Thunder, Review/@comment-49.176.2.253-20130222143229/@comment-4829046-20130223125857

Its only pure speculation to think Mavis isn't strong. We haven't received any hint as to her past yet other than the "fairy Tactician" thing. Also I'm pretty sure she can use all the Fairy Magics, she was the original Master afterall. Also I think maybe Mavis's child form isn't her actual one.