Ayane is Kasumi's and Hayate's half-sister, a Ninja destined to live in the shadow of her older sister. A great hatred burns for Kasumi within Ayane. An expert in Ninjutsu, her deadly fighting style has given her the nickname "Female Tengu". She joins in the Dead or Alive World Combat Championship as an assassin in pursuit of her traitor sister, Kasumi, who left the Mugen Tenshin clan behind. Although she would never admit it, Ayane admires Hayate, Her half-brother.
Ayane also have some connections with Ryu Hayabusa, since he befriends with Hayate and the Mugen Tenshin Clan. In Ninja Gaiden, she plays a minor role, showing a younger Ayane who assists Ryu during his bloody vengeance against the Vigoorian Empire and the Greater Fiend Doku. In Ninja Gaiden II, she appears only near the end of the game, to give Ryu the treasured Dragon's Eye, a jewel that increases the power of the Dragon Sword, Ryu's fabled sword that is said to be made from the fangs of a flying dragon.
In Dead or Alive 3, Ayane's former teacher and foster parent, Genra, the leader of the Mugen Tenshin style in Hajin Mon, has disappeared. Ayane, now as the most powerful Shinobi in Hajin Mon, learns that Genra has been turned into a puppet by DOATEC and its dastardly Omega Project. Seeing what has become of her beloved father, Ayane realizes that the fate commands her to put Genra out of his misery.
In Dead or Alive 4, Ayane has pledged her life to her half-brother and Mugen Tenshin Clan leader Hayate in his cause to destroy DOATEC for all the suffering the company has caused the ninja clans. Ayane has a threefold stake in this revenge trip in that Raidou was changed by DOATEC into a monster, Hayate was brainwashed in DOATEC's attempt to realize Project Epsilon, and the brainwashing and death of Genra.