Warning: Contains SPOILERS for The Batman.
Barry Keoghan's Joker is the one to say "Riddle me this," in riddles and clues left throughout The Batman. Usually in the form of written notes addressed to the Batman, the challenges help to showcase the Dark Knight as the World's Greatest Detective, an element oft-missing from his movies.
The Riddler serves as The Batman's main villain for most of its runtime, but there's a tease of a new threat in the form of Joker as another Arkham prisoner. The Joker is there to welcome the Riddler to Arkham, which hints at a surprising new friendship between the pair. And while the Riddler gets to deliver plenty of fun riddles in The Batman, arguably the most memorable of all goes to the Joker, who poses the brain-teaser: "The less of them you have, the more one is worth."
Just as fascinating as the Joker's riddle in The Batman is how he prefaces it. Notably, the Riddler never says "Riddle me this," in the movie, and instead, it's Keoghan's new Joker who does. It's a big change to both characters, but fits with how they're portrayed in The Batman as well as laying the groundwork for more to come in potential sequels.
Why Joker Says "Riddle Me This" In The Batman (& The Riddler Doesn't)
The Batman's Riddler may leave a series of riddles and clues for the Caped Crusader much like the version of DC Comics, but he deviates in some big ways too. He goes by the name Edward Nashton, rather than Nygma - a reversion to the character's original surname, but certainly the less commonly used one. Similarly, this take is less cartoonish a villain, instead taking cues from the Zodiac Killer in how he plays mind games with Batman. To that end, it makes sense the Riddler doesn't say "Riddle me this" in The Batman, as it would be more in keeping with takes on the character this looks to move away from, with Dano particularly different from Jim Carrey's Riddler (who used the line several times in Batman Forever) and Frank Gorshin's from Batman 1966.
Having the Joker say "Riddle me this" in The Batman is a fun way to include the catchphrase and subverting what viewers might expect, and is still in keeping with his character. Given the riddle ends with both Joker and Riddler in a fit of laughter, then it effectively becomes more like a joke, and so the setup and apparent punchline is befitting the Clown Prince of Crime. Using the line is the Joker's way of having fun with the Riddler, setting up a possible friendship but also showing how he sees everyone as someone he can have his own warped sense of play with.
What Joker's Riddle At The End Of The Batman Means & Sets Up
Following the Joker's riddle, the Riddler himself gives the answer: "Friend." Showing the value of having truly close friends, the riddle sets up Joker and Riddler developing one such friendship - in essence, becoming the only friend the other one has. That could play out in The Batman 2 or 3, with the duo forming an alliance to take down Batman, since both have a history with him and a reason to want revenge. Of course, Joker and Riddler teaming-up would likely be an uneasy relationship - the pair have shown plenty of dislike for one another in DC Comics, and ultimately both would want to be the one who comes out on top against Batman, which would mean bettering the other. To that end, Joker setting himself up as Riddler's "friend," only to eventually turn against him, would help make his riddle a dark joke.
The Joker's riddle near the Riddler's villainous plan, then the location itself will likely be low on many valuable resources, meaning Joker's riddle also reflects the predicament the city is in, something he, Riddler, and other villains could take advantage of in The Batman 2.
