Collider recently interviewed
Arrow showrunner Marc Guggenheim on the return of Manu Bennett's Deathstroke to the show and his larger presence in season 6.
Guggenheim commented, "It was a function of… you know, DC control these characters. We went through a period where DC was like, ‘We’ve got plans for Deathstroke that don’t include
Arrow.’ That changed at the end of this year,” Guggenheim explained.
It doesn't take much to read between the lines and draw the conclusion that Matt Reeves' vision for
The Batman doesn't include Deathstroke. When Reeves previously stated that he wanted a "detective, noir driven Batman" many fans surmised that his take had no room for a psychical adversary like Slade.
For that matter, no one's entirely sure whether Deathstroke is in
Justice League as the only clue is an upside down shot of Zack Snyder reviewing storyboards. There's some confusion as to whether that storyboard was for JL or if Snyder was assisting Affleck back when he still planned to direct himself in the DCEU's first solo film for Gotham's Caped Crusader.