User blog comment:IamJakuhoRaikoben/Chapter 411: Quid Pro Quo, Review./@comment-11721917-20141201142357/@comment-3290324-20141201201329

Well, true enough Zeref is human, but he's a 400 year old, badass human Mage. And supposedly the most powerful Dark Mage in history at that. Regardless of whether or not Gray had demon slaying capabilities, a spell that was tailor-made for a Mage of Zeref's caliber should have obliterated Gray and Natsu. Although perhaps Mard underestimated Zeref. He doesn't think to highly of humans after all. >_>