Today we have learned that Lexa Doig will be joining the cast of Arrow with the 10th episode as Talia al Ghul. This is the daughter of Ra's al Ghul (Matt Nable) and sister of Nyssa (Katrina Law). Talia has a long history in the Batman comics and has appeared in The Dark Knight Rises played by Marion Cotillard. But who is she? Let's take a look at the comic book history.
Talia grew up traveling the world at her father's side, learning from him and eventually becoming his second… an astounding feat as Ra's looks down upon women as inferior. Talia has an interesting and somewhat romantic relationship with Batman, first coming across him when he rescued her from Dr. Darrk (not to be confused with Damien Darhk). Darrk worked for Ra's but failed on his mission and tried to use Talia to save his own life. Batman comes to the rescue, but Talia ends up having to kill Darrk to save the Caped Crusader. They would meet again when she and Robin are kidnapped in a test to find out if Batman would be a suitable heir for Ra's.
She would become an ally to Batman over the years, but when Jason Todd was killed and then brought back to life by Superboy Prime with a reality altering punch (yes, that really did happen), the League of Assassins find him still broken in mind and body and take him to Ra's. It's Talia who sneaks him down to the Lazarus PIt and heals him, telling him that Batman had let Jason's killer live, then sending him on his way.
This is where Nyssa comes in. Seems Ra's had fallen in love with a Russian woman and had a daughter… Nyssa. He then left them to be tortured and die. Nyssa survived and built up a fortune. She then plotted to use Talia to kill Ra's. She killer her half sister then tossed her into the Lazarus Pit, then killer her again. She did this in rapid succession until Talia was broken and susceptible to being brainwashed. Nyssa's plan included an assassination attempt on Superman using a Kryptonite bullet stole from the Bat Cave. Batman stopped the assassination, but was unable to stop the girls from killing Ra's… but Ra's wanted them to kill him, meaning that they have fulfilled their destiny as his heirs and took over the league of assassins together… and they both hate Batman now.
It then comes to light that Talia has a child from a night she spend with Batman. The boy, Damian Wayne, was trained by the League of Assassins, but Talia uses the boy as a pawn in an elaborate and eventually unsuccessful scheme. But the bond between Damian and Bruce began to grow and eventually Talia and Damian try to help Batman and stop the Black Gloves plot, but they arrive too late and discover Batman has died. Talia leaves Damian in the hands of Dick Grayson who takes on the role of Batman with Damian becoming Robin.
But Damian was once again a pawn, having had a chip implanted in him that Deathstroke would use to control the boy and make him kill Grayson. But that plan is stopped and Damian fully sides with his father upon his return. Talia begins to clone her son, giving the clone the name The Heretic. The clone ends up killing Damian and Talia confronts Bruce, only to be killed by Kathy Kane. Both Talia and Damian were buried, but Batman would later discover that both of the bodies were missing.
So… what can we pull from this for Arrow? I don't think Talia will show up in the series with a clone of Oliver's son, but her and Nyssa could work together to supplant Malcolm Merlyn as the head of the League of Assassins…