Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.
Q: Context: Talia al Ghul is the daughter of the supervillain Ra's al Ghul, half-sister of Nyssa Raatko, on-and-off romantic interest of superhero Batman, and mother of Damian Wayne (the fifth Robin).
Question: Which woman was the sister of Talia al Ghul?
A:
nyssa raatko