As a member of the Kisaragi Foundation, Rei shows a serious and competent side. While she maintains her usual cold disposition, she cares more about others than she lets on. Befitting of her occupation as a professor, She acts mature and professionally most of the time, making her seem cold and look older than she really is. She absolutely dislikes having her time wasted, always to the point quickly and speaks in a blunt manner. She can also be condescending towards others. 