Kasumi is a nukenin ("missing shinobi") and former member of the Mugen Tenshin clan, who debuted in the first Dead or Alive back during the 1996 arcade release. She was the winner of the first Dead or Alive Tournament. Originally second-in-line for the title of clan master within the Mugen Tenshin, Kasumi became nukenin, after she ran away from home in order to avenge her older brother, Hayate. She is also the half-sister and cousin of Ayane, as well as Honoka's cousin.