Following the critical and financial success of the Oscar-winning Joker, many DC fans wanted director Todd Phillips and star Joaquin Phoenix to make a sequel to this morbid story about the Clown Prince of Crime and his movement in Gotham. The duo kept it vague, though, making it seem like while they were entertaining the idea, a sequel just wasn't their style. Well, after quite a bit of speculation, it's finally been confirmed that a follow-up is in place titled Joker: Folie à Deux. Interestingly, given what the title means, it's actually the perfect place to introduce Joker's best sidekick.
Of course, many will jump to Harley Quinn, but this is none other than Punchline, aka Alexis Kaye, who debuted in James Tynion IV and Jorge Jiménez's Batman. Now, Harley's a lot of fun, but her wacky style just doesn't fit this grimy, grounded universe. In fact, Margot Robbie already has that corner booked in the DC Extended Universe, helping out the Suicide Squad and Birds of Prey.
And even if DC wanted to work in a new version of Harley, she's not the best fit for this story. Harley's an enabler and a puppet struggling to resist and break free. Punchline, on the other hand, while she's gotten subjugated to an extent, she's still more of a weapon with personality and agency. In the comics, she played a major part in Joker War, overseeing the burning of Gotham while nudging Joker to cause more chaos.
Thus, her chemistry career and love for anarchy match the riots that took place and the unsettled folks who looked up to Joker as a symbol raging against the machine when Phillips' movie ended. The sequel can look at her harnessing her talents from the comics, not just in building bombs but also in using social media to get Gen-Z involved, making the Joker army bigger.
Harley's never really been about growing a movement en masse like this, after all. But Punchline loves it, especially as she's got an ego that needs sating. That can create conflict with Arthur Fleck, who was anxious and introverted, possibly realizing he unleashed a monster in this protégé -- one who prefers society eating itself rather than trying to rebuild the way Arthur envisioned.
That connects to the title as "folie à deux," which means delusions shared by two. Rather than partake and be a tool, Punchline could hijack the legion, become an even darker Joker and turn the movement on Arthur -- making it a story of two villains with differing brands. Having her backstab Joker would fit what she ended up doing in the comics and provide that threat from within that he never saw coming, which would ultimately constitute the cruelest joke possible on the clown.