4) Mercilessness
In The Dark Knight, The Joker was happy to allow Batman to pursue him, and proceeded to malevolently toy with the Caped Crusader like a cat with a cornered rodent. At one point during the movie, the villain’s warped sense of humour comes out in full force as he dangles from a multi-storey building.
“Why do you want to kill me?” the Bat roars at his enemy. The Joker can’t help but laugh. “I don’t wanna kill you!” he replies. “What would I do without you?” There’s a more than a hint of sincerity in there, too – he’s a bad guy who gets off on torturing Batman, not defeating him.
Leto’s Joker on the other hand might not be so willing to keep his enemies dangling on a string for his own enjoyment. Indeed, he may just give them a taste of what’s about to happen (“I’m just gonna hurt ya. Really. Really. Bad”) before flipping straight to kill mode.
Leto’s Joker could display a new level of mercilessness that we’ve never seen before from a cinematic comic book villain – the kind that makes even the most steadfast viewer turn squeamish.