Mrs. Ishii was the mother of O-Ren Ishii and wife of Mr. Ishii. While being held hostage by one of Yakuza boss Matsumoto's men, Mrs. Ishii witnessed her husband die much to her distress.

Seconds later, Matsumoto dragged Mrs. Ishii onto the bed and killed her by impaling her in the chest with the same sword one of his associates had used to kill her husband.