Natsuki Mitobe is a 155 cm tall high school student with a slim build and pale skin. Her measurements are 97-54-87 cm with an I-cup bust. She has waist-length claret hair, frequently styled in curtain bangs and tied in a ponytail or decorated with ribbons. Her eyes are red and tareme-shaped, giving them a drooping appearance.

Raised in a severely strict traditional household, Natsuki embodies refined, serious, and old-fashioned values. She views herself as the legitimate future wife and protector of Kazuya, embracing this role with intense dedication due to her upbringing. This conviction fuels persistent jealousy toward her rival Kasumi, whom she perceives as vying for Kazuya's attention. When provoked by Kasumi, Natsuki readily employs her katana, showcasing volatile possessiveness.

As a member of her school's Serious club, Natsuki specializes in kendo, swordsmanship, and magic/ESP combat. She masters the Mitobe flow technique "Full Bloom Lotus" and excels in dueling and traditional arts like cooking and drinking. Her weaknesses include computer operation and swimming without floatation devices.

Her wardrobe features school uniforms, hakama, maid dresses, cheerleading outfits, tank tops, miniskirts, thigh-high stockings, and hair ribbons. She often incorporates bandages or sarashi into her attire and carries a bokken or katana, underscoring her martial expertise.

Natsuki maintains friendships with Meiri, Kasumi, Mia, and Ai, though her dynamic with Kasumi remains contentious. She attends a school with dormitory accommodations for students.