I still don't understand why did he make her stay as a slave, couldn't he just say no to the slave trader when they're about to do the ritual? Or couldn't he get a slave removal ritual by someone who knew about it, I mean he have a lot of money so that isn't a problem, also I bet that If they ever think of that in the future Caro will be like "no I want to stay as your slave, this slave symbol is a symbol of when we met" or some shit like that