Cain desired a perfect partner with whom to carry out his assassination plans. Attempts to train young children resulted in failure, so he decided to conceive one himself. He found the perfect mother in a martial artist named Sandra Wu-San. He watched her duel her sister at a tournament and concluded that it was her sister Carolyn that was holding Sandra back from her full potential. He murdered Carolyn and ambushed Sandra with the help of Ra's al Ghul and his League of Assassins. In exchange for sparing her life, Sandra agreed to bear David's child and leave the child in his care for him to train.