Notice: spoilers for the Harley Quinn series on HBO Max
There are extremes that are condemned to face for the rest of eternity. It happens in the best houses: Star Wars, Game of Thrones, Marvel, DC… In this sense, Batman and Joker perfectly represent two sides of the same coin. They are two characters condemned to confront each other, but without ending up killing each other… at least in most cases.
Batman and the Joker's relationship is very, very complex. Batman does not kill him because his ideals prevent him from doing so and because he maintains a faint hope of being able to help him. Joker doesn't blow him up because his entire existence revolves around Batman. Without him, no one could stand up to him and plunging Gotham into misery wouldn't be as much fun. Although the Dark Knight knows perfectly well who the clown is, the latter is not the least bit interested in the other's secret identity.
And I'm sure you can cite cases where the Joker has unmasked Batman, but in general he has never had a genuine interest in who is hiding behind the mask. The reason is very simple: he would take away all the mystery and his dance of violence would be much more boring. Nolan's Jokers, Arkham (Origins, City and Knight) and Alan Moore (The Killing Joke) backed out when they proposed it.
No no! Are you fucking with me? What's wrong with you? Don't you think she would have done it if she wanted to? Half the fun of our relationship was the mystery. Now I know that Batman is a rich bore with problems with his parents. Thanks for ruining the most fun he had. Now I don't even feel like torturing him.
We find definitive proof in the animated series of Harley Quinn, available on HBO Max. Joker is celebrating his birthday with Scarecrow and with Batman tied to his throne. He complains that he is bored, despite having the Dark Knight tied up. Finally, Crane removes Batman's hood and Joker takes it very hard that he has been spoiled that the hooded man is Bruce Wayne. In short: Beware of spoilers!
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