User blog comment:IamJakuhoRaikoben/Chapter 438: The Seventh Guild Master, Review./@comment-24039234-20150601171314/@comment-7418318-20150604094602

To me that sounded as if you meant that everyone was fighting against Natsu=END and Mira would weaken Natsu.

What I proposed was the other way round, that Mira=END becomes the boss and Natsu fights together with the other mains, instead of against them.

To elaborate a bit: Natsu becomes END, but is able to keep it from doing any harm, due to the two sides of him battling within his mind.

Mira tries to draw END out of Natsu, but it doesn't work at first, until Natsu wins the internal battle within his mind/soul/whatever (probably thanks to some encouraging words from Lucy).

Now Mira can draw the demonic parts of Natsu into herself, but is intitially overwhelmed by it's power. Now all the main characters together fight against Mira and eventually END is subdued or destroyed.