User blog comment:IamJakuhoRaikoben/Chapter 375: Supernatural, Review./@comment-24039250-20140314193110/@comment-2214433-20140314193522

It wasn't blasted anywhere, I think. It stayed in the Grimoire ship after Zeref killed him. And since Franmalth claimed he had followed Zeref at that time, it isn't too unbelievable that Franmalth found it soon after Tenrou got attacked by Acnologia.