The Joker is, as always, pretty much everywhere. The Dark Knight's premier adversary is starting to outgrow their relationship, at least supposedly, as Warner Bros. look to include the character in several films going forward.
There's the Suicide Squad sequel, the purported Joker/Harley "rom-com" (blegh), another solo film involving Jared Leto's character, and a few other appearances sure to follow. The one worth the most attention, however, is WB's planned origin story being produced by Martin Scorsese and written by Todd Phillips. Joaquin Phoenix is set to star as the titular character, which is said to be a loose adaptation of Alan Moore and Brian Bolland's seminal, albeit controversial comic, The Killing Joke.
Phillips et al. should tread carefully however. The Clown Prince's origin, though detailed in that particular storyline, has never been definitive; part of the fascination surrounding the character stems from the fact that he's constantly changing, and that no one truly knows his story. As the rogue says in Moore's comic, if he's to have a past, he'd prefer to be "multiple choice", and with so many Joker stories to choose from, the old adage applies to audiences too.
With schemes involving murder, Dick Sprang-style murder machines and even fish, these are the stories that'll make this particular film one worth exploring.