Toshiko Kasen appears as a Major Character in GTA Liberty City Stories.
She feels neglected by her husband, so she employs Toni Cipriani, member of the Leone Family, to ruin and humiliate her husband. She pays Toni for tasks such as destroying a Yakuza tank, stealing a Yakuza munitions delivery or destroying money being moved by the Yakuza.
Lastly, she asks Toni to kill her husband, which he does in a Katana fight.
Now having been freed of Kazuki, and wishing for ultimate freedom, Toshiko commits suicide by jumping out of her apartment window.