Yes you've read that right, Joker will return in Batman: Arkham Knight but how can this happen? It seems that in Batman: Arkham Knight the "Joker returns" scenario will happen but it's different from what you think.
Rocksteady has officially stated that Joker is dead as of the ending in Arkham City, however they continued to say that the story of Arkham knight is how would Gotham be if the Joker is gone. They continued to say that Joker is going to be referenced left and right though out the game.
It has been rumored that Joker will make an appearance via Flash backs and through a "dream sequence" when Batman gets intoxicated by Scarecrow's fear toxin.
Fans are also not ruling out a possibility that the secret identity of the "Arkham Knight" is Joker himself.
What's huge however is that Superman is rumored to appear in Batman: Arkham Knight.
It has been rumored that in the upcoming Batman: Arkham Knight videogame, Rocksteady will drop in hints that the Justice League exists in the game "world" via radio messages Batman will come across in the game. Batman will pass by open radio's where the newscasters will report on various members of the Justice League are saving one part of the world.
It doesn't stop there though, it has been speculated that Superman himself will make an appearance. In the rumors, Superman will stop by at Gotham City and he will ask Batman if he could help out. Batman will reject Superman's offer (either in an annoyed "I don't need help" tone or it will be a simple and polite refusal) and either way, Superman will leave and he won't be seen in the game again.
