Christian Bale as Bruce Wayne / Batman:A billionaire socialite who, after witnessing his parents' death in a mugging at age 8, travels the world for seven years before returning home to operate as a bat-masked vigilante hailed as Gotham City's "Dark Knight", using fear against the city's criminal underworld at night. Bale said he was confident in his choice to return in the role because of the positive response to his portrayal in Batman Begins. He continued training in the Keysi Fighting Method and performed many of his own stunts, but did not gain as much muscle as in the previous film because the new Batsuit allowed him to move with greater agility. Bale described Batman's dilemma as whether "[his crusade is] something that has an end. Can he quit and have an ordinary life? The kind of manic intensity someone has to have to maintain the passion and the anger that they felt as a child, takes an effort after a while, to keep doing that. At some point, you have to exorcise your demons." He added, "Now you have not just a young man in pain attempting to find some kind of an answer, you have somebody who actually has power, who is burdened by that power, and is having to recognize the difference between attaining that power and holding on to it." Bale felt Batman's personality had been strongly established in the first film, so it was unlikely his character would be overshadowed by the villains, stating: "I have no problem with competing with someone else. And that's going to make a better movie."Michael Caine as Alfred Pennyworth:Bruce's trusted butler and confidant, who supplies useful advice to Bruce and likeness as a father figure, leading him to be labeled "Batman's batman".Heath Ledger as The Joker:A psychopathic illegalist mastermind portraying himself as an "agent of chaos", who rises from the criminal underworld by thrusting Gotham into anarchy and drawing Batman ever closer to crossing the fine line between heroism and vigilantism. Before Ledger was cast in July 2006, Paul Bettany, Lachy Hulme, Adrien Brody, Steve Carell, and Robin Williams publicly expressed interest in it. However, Nolan had wanted to work with Ledger on a number of projects in the past (including unsuccessfully approaching Ledger for the role of Batman in Batman Begins) and was agreeable to Ledger's chaotic interpretation of the character. When Ledger saw Batman Begins, he had realized a way to make the character work that was consistent with the film's tone: he described his Joker as a "psychopathic, mass murdering, schizophrenic clown with zero empathy". In the film, the Joker has a Glasgow smile, and his trademark chalk-white skin and red lips are makeup rather than the result of chemical bleaching, as in the traditional portrayal of the character. Throughout the film, the Joker states his desire to upset social order through crime, and comes to define himself by his conflict with Batman. To prepare for the role, Ledger lived alone in a hotel room for a month, formulating the character's posture, voice, and personality, and kept a diary, in which he recorded the Joker's thoughts and feelings. While he initially found it difficult, Ledger eventually generated a voice unlike Jack Nicholson's character in Tim Burton's 1989 Batman film. He was also given Batman: The Killing Joke and Arkham Asylum: A Serious House on Serious Earth, which he "really tried to read and put it down". Ledger also cited A Clockwork Orange and Sid Vicious as "a very early starting point for Christian [Bale] and I. But we kind of flew far away from that pretty quickly and into another world altogether." "There's a bit of everything in him. There's nothing that consistent", Ledger said, and added, "There are a few more surprises to him." Ledger was allowed to shoot and mostly direct the videos the Joker sends out as warnings. Each take Ledger made was different from the last. Nolan was impressed enough with the first video shoot that he chose to not be present when Ledger shot

Question: What makes being batman difficult?
Answer: to have to maintain the passion and the anger that they felt as a child