User blog comment:IamJakuhoRaikoben/Chapter 417: A Lone Journey II, Review./@comment-7418318-20150127233426/@comment-83.253.84.32-20150128015722

His memory manipulation on the Fairy Tail members wore off because they figured out that they could not remember anything about him except that he was on Tenro Island for the S class test before and that he could not possible be Mystogans student like he said he was. I think they said that memory manipulation magic stops working if the victims understands that it does not make any sense. The love magic that was used on Lucy in the beginning of the series before she met Natsu and Happy wore off in a similar way.