That's right, not Talia. The other one.
TV Guide revealed that Spartacus actress Katrina Law has been cast as Nyssa al Ghul in an upcoming episode of the CW series Arrow. According to the article, Nyssa is "a powerful member of the League of Assassins, who comes to Starling City in pursuit of The Canary."
Nyssa will make her debut in Episode 13 of this season, which is titled "Heir of the Demon" and will probably air in early 2014. Law is the third person from Spartacus to appear on Arrow, after series regular Manu Bennett as Slade Wilson/Deathstroke and guest-star Cynthia Addai-Robinson as Amanda Waller.
The character, created by Greg Rucka and Klaus Janson, first appeared in 2003's Detective Comics #783 as Nyssa Raatko. In the limited series Batman: Death and the Maidens, comics fans learned that Batman villain Ra's al Ghul had another child out of wedlock during his time in Russia during the 19th century, making her the half-sister of his first daughter Talia al Ghul. Nyssa was later killed off in 2006's Robin #148, when her car suddenly explodes and her death was confirmed by Lady Shiva in the following issue.
With Marion Cotillard appearing as Talia in the 2012 film The Dark Knight Rises, introducing Nyssa seems a clever way to feature Ra's al Ghul story elements on Arrow without showing Ra's and Talia, who may be restricted from being used elsewhere by Warner Brothers. However, rumors persist that Summer Glau's character Isabel Rochev is actually Talia, so perhaps the rights aren't that restricted...
Arrow airs on The CW on Wednesdays at 8 p.m. EST.