Haruka Hasegawa is a postgraduate student. She wears a lab coat over revealing clothing. She is a violent, somewhat sadistic woman from a wealthy, over-protective family.

Her family arranged a marriage for her, against her will. However, she does not have to marry until she is finished with her studies at the university. This is the main reason why she decided to stay there until she receives her doctorate. Hasegawa is not very good at communicating with people, and her harsh personality is used to mask this handicap. She has known Itsuki since she was in middle school.