The inclusion of Zsasz in Birds of Prey (and the Fantabulous Emancipation of one Harley Quinn) shows that the movie will still be plenty dark, despite Harley Quinn’s inclusion and the long and humorous subtitle.
Gotham City is a dangerous place with a thriving criminal underworld, and it’ll be great to get a deep dive into that world with Birds of Prey.
Black Mask may be largely a typical Mob Boss, but Victor Zsasz provides a psychological threat, as well as physical.