The Joker is a character orginally from Batman who appears in some of the Tony stories.
In this movie, The Joker is a mixed combination of the Jack Nicholson Joker, Heath Ledger Joker and Cesar Romero Joker. After robbering juvelery at Vita fläcken, he hides in Tony's room at Thorild and later escapes when Tony arrives the following morning. Later, Tony teams up with Batman and Robin in order to stop the Joker, and as Tonkaboy, he fights against the Joker. Later in the end, The Joker dies when he falls from his helicopter after trying to escape from Tony's roof.
In this book/movie, The Joker appears as one of the enemies the group has to battle in order to progress to the main villian. The Joker also breifly appears in the end, and dies after he falls into the giant hole that the group passed earlier.
In this movie, The Joker appears as one of the villians that guards one of the clues together with The Riddler. However, after Joker and Riddler is deafeted, the new team member Gregor Samsa turns out to be Bozier in disgusie, and The Joker is brought back to life. However, he is once again deafeted and is presumably sent to jail.