User blog comment:IamJakuhoRaikoben/Chapter 463: Black Carpet, Review./@comment-1776824-20151123213644/@comment-1776824-20151124060815

Except they aren't even sacrificing him. They literally think he can defeat Zeref with his secret technique. There is absolutely no doubt in their minds that he is going to come out of this on top, disregarding that the fate of the entire human race rests on his ability to land said untested, ultimate skill, that they have never seen, and have no idea as to the abilities it possesses. He needs back-up. Your wording of this being a play of sacrifice for the furthering of the war is false. Your idea itself is also false, for if they sent someone to go and assist Natsu, there is no way they would ever believe that person would die. They would send them in good faith, but instead, they are just letting Natsu run wild, ignoring his ungodly high (and definite from an out-of-universe perspective) chances of failure. And it doesn't change the fact that Gray being there would also make the story 10000000x more interesting and re-introduce the END dynamic in a more tense, dramatic situation. Having Gray potentially witness transformation of his best friend to the object of his fury > Natsu just failing his shit, transforming, Gray finding out about it second hand. It's just bad writing on every single account, what Hiro's doing right now.