Mrs. Kiriyama (full name unknown) is a minor character in Battle Royale.
Backstory[]
Mrs. Kiriyama was the mother of Kazuo Kiriyama. As soon as he was born, Kazuo could remember his mother was always happy. She would always be impressed with how her child would cope with things as he was very cheerful and helpful, while being smart.
One night would change everything. Mrs. Kiriyama, Kazuo, and their driver were hit by a sleeping truck driver. She would lose her life, while her son would lose his emotions as a result of the accident.
In Kazuo's Contestant Info, it implies his mother had an affair.
When Kazuo regained his emotions after being shot by Noriko Nakagawa, he simultaneously felt a rush from being shot and the trauma and grief of losing his mother, causing him to practically beg to "go back to the grey".