Not much is yet known about David Ayer’s upcoming film Gotham City Sirens other than that he is attached to direct and will reunite with Suicide Squad’s Margot Robbie, who will reprise her role as Harley Quinn. However, Ayer have just revealed who the film’s main antagonist will be.

Ayer shared an image of longtime Batman villain Black Mask on Twitter without a caption, suggesting that the character is featured in Gotham City Sirens in some way. While posting an image of a comic book villain to Twitter is definitely not confirmation of anything, it’s important to note that Ayer did something similar for Suicide Squad with Jared Leto’s Joker.

Black Mask, a.k.a. Roman Sionis, has been part of the DC Comics universe since 1985 when he was introduced in Batman No. 386. A crime boss with a penchant for sadism and mask collecting, Black Mask would be a logical choice for an antagonist in Gotham City Sirens, especially given recent events in the comics, which has seen the crime boss engaged in a bitter rivalry with Catwoman (one of the film’s main characters) for control of Gotham’s criminal underworld.

Gotham City Sirens was announced late last year and currently has no expected release date.