Shiho Hasegawa

Originally a main character in the fangame Corpse-Party ZERO, she's now considered part of the official canon after being mentioned and appearing in some official media. In Musume, she's found dead by Yoshiki Kishinuma and Ayumi Shinozaki. We are shown that she died protecting her sister in a flashback; however, she bears a grudge against Kaori Hasegawa for not helping her and believes she was betrayed by her. Like in Corpse-Party ZERO, she refers to Kaori as "Sister dearest" (or "Nee-sama").