That demon is going to regret getting freed from imprisonment, on the side note I still ship the demon king and the knight girl
SPOILERS!!!!!!
If I remember right in the novel the mc goes "DARK" at this points and goes "WILD" with his abilities as he attacks her to the point he almost kills her and then they take her with them back home where she becomes their slave.
In the novel it is stated the demon girl begged them to do it as she earned them her "strange AND weird" respect in a slight masochist way which causes the mc and his wife some awkward situations when she blurts out she is his slave despite the mc asking her NOT to do it she still does it.










So from the wn spoilers I have read
The one who kidnapped Filimina was Luna who is basically entitled and crazy, wants to be together with Eddie claiming she is a better fit than Filimina.
(She says crap like shes better looking and etc, and stabs Filimina)
Up till the end when Eddie and the others went to go rescue Filimina, Luna believed that Eddie would love her or already loves her
Apparently Selves and Luna were fiancee's, and she made him curse Filimina because her family was more powerful than his and etc. (I felt sorry for him at first but I read that even though he loved her, he wouldve still cursed Filimina because he hated Eddie more ╮( ̄▽ ̄)╭)
At the end, Filimina apparently bitch slapped Luna which is something I want to see
Thanks for spoiling me. Not knowing would have kept me up all night.