How to evaluate the clown role played by Sisledger in The Dark Knight?

In the movie, everyone who talks to the clown is more or less inspired by the dark side of his heart. Clowns become more and more clear and complete in every talk show. Heath Ledger explained it in different ways. Squinting scornfully at the guards and calling colleagues cowards. If a person has no affection, love and social attributes, what is left? Basic human nature? The clown thinks that even in extreme cases, human nature is despicable and evil. I brainwashed Harvey in the hospital. The clown's character, existence value and appeal have been fully reflected. These well-structured and exciting performances are great. On the set, when Heath Ledger is about to start performing, the idle staff will gather behind the camera to watch, because everyone knows they can't miss it. As Ang Lee said, "Even if he is only a supporting actor, he will steal the whole movie and the whole performance." There is no doubt that he is an excellent actor, who has created eternal roles beyond performance.