User blog comment:Miskos3/Fairy Tail 538: When the Flame Goes Out, Review/@comment-7418318-20170602143852/@comment-7418318-20170602151202

But she did it in a book that was going to disappear... She saw the book disappearing right before her eyes, so it's only natural that anything that was written inside - including her changes - would disappear as well.

The only ways I can see that she could have done to keep Natsu around (if he's really gone) would be to either disconnect the book from Zeref, so it continues to exist after his demise, or to disconnect Natsu from the book, so he can continue to exist after the book is gone.

But she did neither, so I am surprised that she is surprised that her method of (not) solving things didn't work out.