Sanae is a female high school student who is also one of Kōshi's friends. She is also his class representative. Unknown to everyone, however, she changes into a heroine known as Tenchū Senshi Uma Kamen, literally meaning "Divine Punishment Warrior Horse Mask", the identity she uses to fight as a superhero. She is apparently also the granddaughter of Iroha's and Hanzō's landlady. Both she and her grandmother are masters associated with the horse of the zodiac. As the chosen protector of the Inuzuka heir, Sanae has been given her tribe's special outfit to wear, which increases its wearer's power. Alas, the outfit closely resembles a bondage costume and is most effective when less of it is worn; when the wearer only has certain pieces of the costume equipped, their power is highly focused in the parts covered. In the Nakajima family, kicks are the central part of their combat style, so the costume is most effective for Sanae when she wears nothing but the boots. Needless to say, Sanae finds the costume embarrassing enough when wearing all of it.