Osana Najimi

In the beginning of the game when you run into Senpai, you're also seen by a blonde girl with pigtails. This girl is most likely Senpai's little sister, - or imouto - as it has been mentioned by the Dev several times. She's seen wearing the same white and blue uniform and black stockings, like Yandere-Chan 's default outfit.. She cannot be murdered (yet?).