Honkai Impact 3: Dimension War

[Single heroine + protagonist group + good ending] Note: This is Honkai Impact III of another dimensional universe, not Honkai Impact III of the main world. In the vast snow, a boy is carrying a girl on his back, and the girl is lying quietly on the boy's back. "Ayu, if, I mean if, if I become a monster and no longer am me, and everyone in the world comes to kill me, what will you do." The boy heard this sentence... "That day will never come. If it does happen, I will stop you. If you can't, then the world will become your enemy!" … This is the first time for a new author to write a book, so please forgive me if the writing is not good. There will be no knives in this book, (probably) if you don't like it, don't spray it, if you don't like it, don't spray it, just have fun (๑❛ᴗ❛๑)