Don't Deliver Us from Evil/Mais ne Nous Délivrez Pas du Mal (1971) - Séria
As far as the 'catholic schoolgirls swear their allegiance to the devil' genre goes, Don't Deliver Us from Evil is a slow burn and a pretty classy one. It concerns bff Anne (brunette) and Lore (Blonde) doing all sorts of little evil deeds - killing birds, setting haystacks on fire, reading dirty books, seducing various men (usually village idiots).... It's all for laughs though, even at times they are in physical danger of getting raped. They are not completely remorseless. Anne cries her hearts out after killing her family servant's pet bird. Director Joel Séria treads lightly on the girls psychology or characterization. You don't really get the sense of who they are. What you get is constant underlying tension as the 'innocent' girls dig deeper into their graves without ever knowing the full consequences. I still prefer Alucarda and Heavenly Creatures over this, but Don't Deliver Us from Evil has some good moments.