Origin - Early Life
Nyssa was the love child of Ra's al Ghul and a Russian woman. It revealed that Nyssa was born when Ra's al Ghul was traveling in Russia. There, Ra's met Nyssa's mother and shortly after, Nyssa was born. Her mother would regale her with romantic tales about her father. Nyssa grew interested in her father and became determined to find him. Nyssa was able to track her father at his headquarters in North Africa. When she showed up, Ra's instantly became impressed with her beauty, intelligence, and how she was able to find him. He offered Nyssa a high rank position in his organization to which she accepted. Ra's would trust her enough to allow her to use the Lazarus Pits.
Nyssa was also the one who discovered a way to reuse the Lazarus Pits over and over. Eventually Nyssa did not like her father's ideal and method, she decided to leave his organization sometime in the 19th century. Ra's thought that she would someday return with children and take his place, but Nyssa had other plans. Nyssa refused to give Ra's a family for possible heirs to his organization, which resulted in Ra's disowning her.
Nyssa was created by Greg Rucka and Klaus Janson.
World War II
During World War II, Ra's had allied himself with the Nazis, and Nyssa and her family were imprisoned in a concentration camp. Ra's abandons Nyssa in the camp, and for that Nyssa resented him and began to plot against him. Nyssa's entire family died and only Nyssa was able to survive after she was let go from the concentration camp due to the Lazarus Pits.
Return for Revenge
Saddened by her gruesome experiences during this time, and furious that Ra's had abandoned her and her family to die at the hands of the Nazis, Nyssa started a plot to kill Ra. She re-entered Ra's life when she befriends her half-sister Talia. However, Nyssa planned to kidnap Talia and brainwashed her into killing Ra's. Nyssa also had plotted a plan to assassinate Superman with a Kryptonite bullet she stole at the Batcave. Her motive was to destroy all hope in the world by assassinating the man of steel. Batman was able to stop Nyssa, however she was able to mortally wound her father. As Ra's laid there dying, he reveals that all this was a part of his plan to make his daughters come to realize that Ra's was correct all along. His plan works and both Nyssa and Talia realize their destinies as their father's heir. The two sisters then proceed to declare Batman as their enemy. Nyssa is the only one who knows where the last Lazarus Pits are and has used it to continue living.
During Infinite Crisis, Nyssa used Talia's membership to the Secret Society of Super Villains to enact her plan. She had intended to use the Society to take over the world and bring it peace and equality. Nyssa tried to recruit Cassandra Cain to join her League of Assassins, but Cassandra declines and along with Mr. Freeze, escaped from Nyssa's grasp. One Year Later, Nyssa is seen in Northern Africa, planning an unknown plot with two terrorists. As she gets into her car to leave, it explodes. Shiva reports that Nyssa is dead, killed by the League of Assassins, and Cassandra Cain had taken over the League.
The episode is "Heir to the Demon" The actress who plays her is Katrina Law.
Her father sends her to retrieve Sarah Lance to bring her back into the League of Assassin's. Which Oliver says that will not happen and conflict ensues between him and Nyssa over Sarah.