That ending makes me wonder, did Gran actually betray Cag knowing he had a replacement for her, or did he just happen to remember? That "JUST AS PLANNED" smile is suspicious.
So, from what I can kinda read, Cagli got mind broken and betrayed Gran, and then Gran got a package from her captors with one of her spare bodies, and Gran feels like he wants a "female" of his own...
@ UnlimitedBlades Gran didnt betray Cag,he just had no way to find her(or him) The criminal burnt the house and there's nothing left, after all this he got his mind broken. At last he even got a copy of Cag from the criminal,which finally led him to go totally mad.
However,seeing Cag getting raped,Gran himself felt more excitement rather than rage or humiliation,maybe this can also be called betrayal.