Casting for Joker is still a long way off; the script has only just been completed, and it remains to be seen whether Warner Bros. will even greenlight the project.
Tell the Truth, Liu Zhou actually likes this movie quite a bit. If copyright issues weren't involved, he could have started preparations on his own without having to defer to Warner Bros.
Although the plot has no connection whatsoever to DC Comics or The Dark Knight, the character of Joker genuinely owes his existence to their IP.
Chapter 534