
As a result of witnessing the killings at such a young age, she was left psychologically and emotionally traumatized. Thankfully, despite her emotional state, O-Ren noticed the fire and managed to escape. Riki, acting quickly to cover up the evidence of that night's horrific events, set the house ablaze. Afterwards, the mob made a hasty departure. Riki handed him the katana, Matsumoto personally executed Mrs. Immediately after her father's death, Matsumoto dragged Mrs. Although he fought fiercely and valiantly, his blind rage clouded his focus, and was subsequently caught off-guard when Matsumoto's right hand man, Riki, surprised him from behind and thrust a katana through his heart. Ishii, a brave man and skilled martial artist, disarm and kill two of Matsumoto's kumi-in. Whilst hiding under the bed for protection, young O-Ren witnessed Mr. However, at the innocent age of nine, her life had forever changed when her home was intruded by assassins led by the ruthless crime boss, Matsumoto, Japan's cruelest Yakuza boss. Her father was a Sergeant Major in the United States Army and her mother was a faithful housewife. It is presumed that her very early childhood was untroubled as little is known about her infancy. After a duel in the snow, O-Ren was defeated and killed by Beatrix Kiddo.

O-Ren eventually became the leader of a crime organization in Tokyo called the Yakuza, where she led the Crazy 88 and Gogo Yubari. She is a half Chinese-Japanese American who was the daughter of a military man and a housewife.

She was born on an American military base in Tokyo, Japan.

O-Ren Ishii (石井 オーレン) (Ishii O-Ren) was a member of the Deadly Viper Assassination Squad known by her code-name Cottonmouth.
