Beatrice Yvonne von Guldenhorf

Her full name is Beatrice Yvonne von Guldenhorf. Her first appearence was in the fourth episode. In it she was using her position of Grand Duchess to bully students, including Tifania for wearing a hat in her presence, being more popular than her, and having ample breasts. Upon learning Tifania was half-elf, she tried to have her boiled in water, under the guise of punishing a heretic, since elves have a different religion than humans. It was later revealed she had no such authority to do this and was stopped by Louise before Tifania was put in the boiling water. Tifania then asked if they could be friends.

Beatrice is followed around by three girls who help her bully people and are generally agreeing with her due to her title. (Source: Wikipedia)