I loved it.
So if I understood correctly, every timeline where Jefuty escapes is doomed because it will always lead to William reverse-engineering a Shrike fully immune individual that can interact with Relics, that being Lusica, and end up destroying the world with it. From the conversation Jefuty had with Kämpfe, it seems activating the Relics en masse will bring about the return of the unknown civilization. Does William even know what he's doing?
I find it funny how for the most part AU is the only one in constant shock of the shit Sugar does. Dolls fighting Shrikes, no fucks given. URNC soldiers, one or two of them go "This doesn't feel right" but otherwise nobody questions the evil red things.