User blog comment:LastationLover5000/Fairy Tail 283 - In Which Nakama Is Spoken (Natsu vs. Sabertooth)/@comment-3030647-20120520044118/@comment-3001427-20120520150120

Its likely that she's an onmyojutsushi, a practitioner of Onmyodo, given the Yin-Yang symbols she used. And no its not a magic that negates all other magic, do you remember what happened outside first? Natsu's attack went off, it just didnt hit the other guy. Onmyodo is all about the flow of energy, its more reasonable to assume that she merely redirected the magical energy of his attack elsewhere. Its a very subtle form of magic, but very powerful in the right hands of a skilled practitioner. Very useful in fairy tail, given that everyone uses offensive based magic. She's likely extremely powerful, if my theory is correct, moreso than even if she possessed the ability to negate any form of magic via a barrier. Afterall, who needs to negate, when I can simply redirect and force you to suffer the effects of your own spell, or better yet turn all that power against your allies? Deadly indeed.