Matsumoto (松本) was a ruthless Yakuza boss in Tokyo, Japan who was responsible for the orders to kill O-Ren Ishii's parents, Mr. Ishii and Mrs. Ishii with himself and his men later fleeing the scene, having set fire to the area to cover up their involvement.

Two years later and at the age of 11, O-Ren, having gone through intense training got her revenge, mainly because Matsumoto was a child molestor by sneaking into his house, disguised as a schoolgirl before disemboweling him, resulting in his death.