Otome Senshi Lovely 5!

from tsundere translations: ogdoas private academy… under the new, young headmistress, freedom, independence and self-fulfillment are the motto of this mission school. however, among the nuns there those who are concerned about order and morals within the school and who oppose the head-mistress's ideas. and without anyone knowing, right now, at this school… a battle between good and evil is about to take place! a continuation to shion and nashida-sensei's story called “teacher's pet” can be found in yuri hime wildrose volume 2