User blog comment:Miskos3/Fairy Tail 535: The Greatest Power, Review/@comment-29778526-20170513015909/@comment-21119641-20170516234542

Mard Geer probably came up with the whole "Sealed" thing, since by opening the book only brings out information, he must have thought there was something else to it.

Also, Igneel was merely mocking Acnologia after hearing Mard Geer's words. Acnologia INSTANTLY dismissed as it is false. Igneel doesn't need to tell the truth to Acnologia, Acno would kill Natsu anyway since he is a Dragon Slayer.