Responses
actually it's revenge for her dead friend (sorry i forgot her friend is dead or not) but she taking revenge for her friend. the ex bf did shit to his ex gf (purple hair bff) so shes taking revenge for her
and the purple hair didn't know our FL and ex bf were together and didn't purposely hurting FL but its too late to prevent that as FL already in relationship with ex bf at that time
so yeah purple hair half kind half shit i guess? but shes doing this all for sake of her bff that have been treated shit by ex bf (red hair)

I didn't believe the spoiler when I read it, but is it really true?? Purple hair bish is purposefully torturing the trash ex-bf and his trash family for the sake of the FL?