The mother coming around and accepting her daughter, I thought this was where it would head with all the power of love crap they talked about in the previous quest. But nope. Instead Riore essentially orders her own mother's execution right in front of her, and Sid obliges in a slowmotion decapitation. Brutal. If this were less cartoonish/censored that would of been a grisly sight.
And if you talk to them after the quest it's implied that she may end up becoming a dark knight herself now, Sid says he would train her if that is her wish.