User blog comment:FairyRaven/Fairy Tail Chapter 303: A Battle On Two Fronts, Review and Commentary/@comment-112.205.76.218-20121012105856/@comment-121.54.2.164-20121012133850

I think it is most possibly Angel. The picture of Yukino's sister resemble Angel's younger self and Yukino herself has some resemblance to Angel when she was first introduced. They even have the same kind of magic. And the "blind believers of Zeref" that Yukino said (In the mangahere translation) reminds me of the ones in the Tower of Heaven since they were seen with their eyes covered. But the possibility of it being Meredy is open but I believe Angel has a better chance.