|Class and Year||1-F|
|Physical and Vital Statistics|
|Manga||Volume 2 Chapter 7|
Ruri Ninjabayashi is an android created by the Mahogasawa Foundation. She serves the as the shinobi in Souta's party, and is introduced in the story as a secret weapon to help the Quest Dorm in the school's athletic tournament games. She frequently asks yes–no questions on operations she is about to perform, and is programmed to act like a little sister to Souta.
Because she is a robot she doesn't show a lot of expressions on her face, but she always want to helps eveyone from the dormitory. She has a reserved personality as Mimori said.
She was created by Mahougasawa electronics, she is an android imouto, newly developed to take the imouto position in a family.
She helps Souta with the flags and removing his death flag.