Ewan McGregor features in Birds of Prey as the powerful and sinister antagonist Roman Sionis AKA Black Mask, who has a personal vendetta against Margot Robbie's Harley Quinn. This animosity surprised many comic book fans since there is little-to-no interaction between the two in the comics. In an interview with Gamespot, McGregor explained the reason behind Black Mask's newfound hatred towards Harley Quinn.

"He has to be in absolute control. He's insane when he's not in control. We only see him in his club, in his car, in his apartment--or at the end when he's running around. But really I feel like we only ever see him in places he controls. And then Harley comes into this world and she's uncontrollable. It drives him mad. He hates it."

So it seems the fact that Black Mask is dealing solely with a newly single Harley, who is no longer doing the Joker or anyone else's bidding, is what created the new dynamic between Margot Robbie and Ewan McGregor in the story.

It is interesting to consider that it was Harley's unpredictability and wild nature that made the Joker fall in love with her, while it is that same unpredictability that has caused another supervillain to target her in particular. McGregor further went on to explain what Harley without Joker by her side means for her standing with his character.

"It plays into the exploration of misogyny in the film. He's only ever put up with Harley because she was Joker's girlfriend. So that was the only reason he ever put up with her, because [Joker] was all-powerful. But as soon as [Roman] realizes that Harley's man is out of the picture, she becomes a problem. That makes him a true misogynist. Harley is trying to find her freedom--the emancipation of Harley Quinn, right? She's trying to find her voice. She's not getting her power from her partner anymore."

This portrayal of Black Mask as a misogynist goes all the way back to the early '2000s. That was when Black Mask tortured and murdered Stephanie Brown, who was Robin at that time, cutting her tenure in the costume short after only nine issues. While Stephanie managed to escape her dire fate, in a convoluted manner possible only within the pages of a comic book, Black Mask became notorious for being at the center of a storyline that many saw as deeply misogynistic based on his treatment of the female Robin.

It seems the movie adaptation of the character is looking to revisit those same anti-women motivations, which makes him a particularly effective villain to pit against an all-female team of superheroes/antiheroes/villains. McGregor's comment about the film's 'exploration of misogyny' makes it seem the movie will go deeper into discrimination issues facing women than any other comic book movie to date. Strange to think that the titular character of such a film is possibly the most notorious female comic book villain in history. This news comes from Game Stop.