User blog comment:IamJakuhoRaikoben/Chapter 480: The Northern Gravestone, Review./@comment-100.15.97.117-20160405022015/@comment-7418318-20160405124119

Through Obra Zeref has detailed information on the GMG, which would naturally also include at least Lucy's full name, so it don't expect anymore more than a short raising of an eyebrow and commenting on how she looks almost exactly like her ancestor.