|This article is about a/an hero in Sekai Ninja Sen Jiraiya.|
Kei Yamaji (山地 ケイ Yamaji Kei?)/Princess Ninja Emiha (姫忍 恵美破 Himenin Emiha?): Tetsuzan's daughter, a 16-years-old high school freshman. She often teases her adoptive brother Toha, leaving most of the housework and chores to him, but cares deeply about him. When she dresses as Emiha to assist Jiraiya, she wears a white ninja armor similar to Jiraiya's. Her special technique, the Cherry Blossoms Rain Ninja Art (忍法花吹雪 Ninpō Hanafubuki?), allows her to put enemies to sleep with a rain of white cherry blossoms. Her other technique, the Face Copying Ninja Art (忍法顔うつし Ninpō Kao Utsushi?), allows her to create face masks of other people to disguise herself.
She first dressed as Emiha when Toha had his fighting spirit stolen by Fire Ninja Chang Kung-Fu. She was tied to a wooden board with Manabu Yamaji but after Toha received a letter from her he gained his fighting spirit back and came to assist her. She then fought Butterfly Ninja Benikiba whilst Toha fought Chang Kung-Fu. Break! The Magic of Fire Ninja Chang Kung Fu