Ayane

Ayane is the half-sister of Kasumi and Hayate. During the events of DOA2, she is ordered by Genra to hunt down and kill Kasumi who had been considered a runaway shinobi because of her departure from her village. However, Ayane fails her task and is defeated by Kasumi in the final rounds of the tournament. Ayane encounters Hayate as well in the DOA2 tournament, but because he was suffering from temporary memory loss due to the Epsilon Project, he did not remember her and they were forced to fight. Also during the DOA2 Tournament, Ayane is confronted by Helena, who accuses her of killing Helena's opera singing mother. The accusation is false, as it's later revealed in Dead or Alive 4 that it was Christie who killed Helena's mother. Ayane does not deny the accusation outright, choosing instead to taunt Helena before they battle.

Credits:
Papacha, and Megaman_Zero from Wikipedia.