1) Joker
Comic Books: Do we really need to explain who the Joker is? The Clown Prince of Crime in Gotham, the Joker is a notorious force of chaos. Whereas other enemies of Batman are fuelled by a thirst for power or wealth, Mr J. – as Alfred famously said – “just wants to watch the world burn.”
Since Harley Quinn transitioned from her breakout role in Batman: The Animated Series to the comics, Joker often has his sidekick/girlfriend by his side. Despite Harley’s devotion to him, though, the Joker never really shows her any genuine affection and is generally highly abusive to her.
DCEU: In Suicide Squad, Jared Leto and David Ayer attempted to update the character by portraying the Joker as a mob boss – complete with that hoary old trope of conducting his business in the back of a strip club. Joker’s feelings towards Harley were also presented, for the first time, as genuine. His entire arc in the film is motivated by his desire to rescue the former Dr. Quinzel from danger. And that’s not even mentioning the character’s radically different fashion style and bodily adornments – tattoos, dental grills, etc.
Like Lex, fans have theorized that this radically different Joker is not the original Clown Prince of Crime, but is actually a corrupted, insane Jason Todd (who’s thought dead by Batman in BvS). However, it’s since been confirmed that Leto’s character is the real deal – whether you like it or not.