Prior to the OVA's events, Emi carries out her eldest sister's plan to viciously murder 76 of her schoolmates from Takanoha Gakuen High School by attaching gas tanks beneath two of the school buses, which later cause all of the students, as well as the drivers, to fall unconscious and drive off a steep cliff to their deaths. Soon after, a new batch of students are enrolled, the parents of whom Gozo plans to exploit in order to further his family's success.
While her sisters ultimately make the heroine, Saki Asamiya, their main antagonist, Emi finds her rival in classmate Junko Yuina, who is a much more gifted artist than she. Gozo bribes the judges at the Shiki Exhibition to choose his daughter's painting, provided that it is a respectable offering. However, after Ayumi plants the seed of doubt in regards to her sister's talent, Emi decides she should take no chances. Emi pays a visit to Junko's small apartment and is overwhelmed as she gazes upon the beautiful, near-finished painting she has created. The following night, Emi instructs two of the family's goons steal the painting and kidnap Junko, who is then brutally raped and drugged throughout the week, and finally murdered.Emi copies the stolen painting exactly and presents it at the exhibit with her father. However, her new success is short lived as Saki and her friend Sanpei crash the party and expose her scam. Both Mizuchis are then arrested by the police, and surrounded by press, to which Emi is thrilled to finally be getting the attention she deserves. Just as they are being carried off, however, another unnamed classmate, who had been hypno-programmed by Remi, shoots and kills both Emi and Gozo, before finally turning the gun on herself.
In the mangaEdit
Unlike her two sisters, Emi is bit different in the original manga versions. On the one hand, she is slightly more reasonable in that she initially prefers to create the winning painting on her own. However, she is ultimately far crueler to Junko via giving her a ride home only to then kick her out of the vehicle and onto the street after discovering that the girl is poor, having motorcycle thugs run over her hand to prevent her from painting, and even having the girl's mother murdered, all before facing the same tragic end from the anime.