A Different Kind of Girls' Frontline

Warning: Most of this story has nothing to do with the official version.

Girls' Frontline really is a tragic incident caused by humanity itself. But what if none of it had happened? What if the things that should have been discovered weren't? What if, instead, there were an infinitely powerful external enemy? (This is a crappy story, and the author is lazy too. I'd recommend not ruining your eyesight over it. If you can't keep reading, just stop.)