Arrow is finally introducing Talia al Ghul.

One of DC Comics' most formidable characters, the oldest daughter of Ra's al Ghul (Matt Nable) has only been seen so far in the Arrow-verse in the past as a young girl on Legends of Tomorrow, but The Hollywood Reporter has learned that she will finally appear as an adult on Arrow later this season.

Lexa Doig (Continuum, Stargate SG-1) has been cast in the major recurring role of the half-sister of Nyssa (Katrina Law). Described as "worldly and cultured, an elite warrior who doesn't pick sides but rather creates her own," Talia is an expert hand-to-hand fighter, extremely well-trained in most weapons and highly intelligent. She will first appear in episode 10 and will recur in multiple episodes this season.

While Arrow has already spent numerous seasons getting to know the rest of the Ghul family through Ra's as the former leader of the League of Assassins and through his other daughter Nyssa, the introduction of Talia has major ramifications for The CW series if it follows the comic book source material. While she is widely known as one of the best DC Comics supervillains, she also has a long and storied history as Batman's on-and-off again love interest. She even had a child with him. While the Arrow producers have always made it clear how much they love Batman, it never seemed like a possibility to have Bruce Wayne on the show while DC Comics currently has both the big screen version played by Ben Affleck as well as the younger version of the caped crusader, a pre-Batman Bruce Wayne, on Gotham. But the producers have never denied the possibility that they could have Batman on Arrow.

"At the end of the day, it'd be so awesome to have Batman on the show. That'd be really cool," executive producer Marc Guggenheim previously told THR. "I don't think that will be happening anytime soon, but you never know… one day. One thing we're always saying… we ended up with a lot more DC Comics characters becoming part of the show than we had ever planned. It wasn't initially part of the pitch or the conception of the show. ... I've learned not to expect anything or make any predictions because the reality has far exceeded any of our initial predictions or initial conceptions."

Throughout Ra's al Ghul's time on Arrow back in season three, fans constantly wondered if the prominence of the biggest Batman villain from the comics meant that Batman would also be introduced on the show, but that obviously never came to pass. Perhaps the producers were waiting until they could tell Talia's story to bring the iconic antihero to the series. There is a lot more story to mine from a complicated love interest like Talia who constantly waivers between her loyalty to her father and her father's organization, the League of Assassins, and her love for Batman, making her a compelling antihero in her own right. She also has connections to other major DC Comics characters like Bane, and even Superman and Lex Luthor, therefore opening up the door to more potential crossovers with Supergirl.

While the speculation surrounding Talia's upcoming arc on Arrow is endless, what is practically guaranteed is that her half-sister Nyssa will return in a big way to the story, as they have a tumultuous relationship in the comics. After Ra's abandoned Nyssa as a child, resulting in her enduring horrific torture in a concentration camp during the Holocaust, she vowed to get revenge on him by using his other daughter Talia. By killing Talia and resurrecting her over and over again via the Lazarus Pit, mentally breaking her and making her into a weapon to kill their father. She succeeds, and the two sisters then take over the League of Assassins together. And since the Lazarus Pit affected Talia emotionally, she renounced her love of Batman and became his enemy after that.

On Arrow, it has been well established that Nyssa had no warm feelings towards her father since he disapproved of her relationship with Sara Lance (Caity Lotz), and even forced her to marry Oliver Queen (Stephen Amell) even though she was a lesbian. And since it was revealed on Legends of Tomorrow that Ra's was already training Talia in the League of Assassins back in the 1960s, the half-sisters could have a complicated backstory that can play out in flashbacks, or in present day. With so many possibilities and different options to choose from, there's no way to predict how Arrow will handle this iconic comic book character, but no matter what, her presence will have a huge impact on the show.

Arrow airs Wednesdays at 8 p.m. on The CW.