"Not even your Bakuzan could cut it off entirely..."
Ragyo will be killed with the Double Scissor Sword.
Satsuki's Bakuzan is fucked so she will get Nui's half of the scissor sword.
It will either be Satsuki who uses the Double Scissor Sword to solo Ragyo after Ryuko throws the red half to her.
Or they combo together with each half of the scissor sword and 2v1 Ragyo, finishing with a flashy synchronized beheading.
That seemed pretty obvious from the onset.