Well it was what I expected. I don't like them giving Acnologia a sob story at the end, come on, no.
So Acnologia he is about to go down, we can't deny that. And the way they build up Acnologia, there is no satisfactory way for him to go down, Hiro created a hole he can't get out of, he over powers his villains way too much.
So I am guessing that little girl is someone important to Acnologia, little sister / childhood friend, I don't think we will ever find out.
I am puzzled why Chelia of all characters gets a little bit of a spotlight here. Did she just get her magic powers back? I bet that happened.
So Fairy Spare, next chapter the battle will be over, and I am sure everyone will rage.