User blog comment:Miskos3/Fairy Tail Chapter 505: Trump Card, Review/@comment-24039234-20161007134701/@comment-24546844-20161007141216

This could easily be solved had Mashima written "a spell of this magnitude will take a bigger magic toll than your body can stand!". Tadah, good explanation and still within the stabilished rules. But nah, Mashima had to create new unecessary rules.