The fans have often wondered – Does Batman exist in the CW/DC TV universe? The answer is in the affirmative. There have been multiple references to the character of Batman in the different seasons. In the Flash episode when Barry goes to Earth-2 to fight Zoom, at his home’s speed-dial we see various names are mentioned, one of the names is Bruce. Further, Geoff John’s Flashpoint comic-book storyline was being adapted for Flash Season 3, where Batman is an integral part of the comic-book storyline. In the Legends of Tomorrow, Captain Hunter says “I have seen Men of Steel die and Dark Knights fall.” In Supergirl, Kara said, “My cousin worked with a vigilante once – tons of gadgets, lots of demons.”
But the most direct reference was in Arrow when Felicity is given a code name Overwatch instead of Oracle as it’s supposedly taken. Moreover, the show has used Ra’s Ahl Ghul who is Batman’s foe in comics.
Here’re four ways in which the Dark Knight can be actually brought into Arrowverse:
Flashpoint 2.0:
Another Flashpoint like event can be created in future seasons which can be used as a plot device to bring Bruce Wayne into the alternate timeline. It would be big missed opportunity for DCEU not to utilise its biggest superhero to the fullest. Perhaps, in the previous timeline, his parents were alive and he didn’t transform into Batman.
Nightwing Solo show: 
DC has been trying to make spin-off shows of sidekicks or other important comic-book characters such as Birds of Prey. The best one would be a Nightwing series based on Dick Grayson coming out of Bat shadows on his own. Bloodhaven has been referenced many times on Arrow, so it wouldn’t be difficult to eventually bring Batman into this world.
Flash Newspaper:
An easter-egg can be dropped in a Flash newspaper containing an article about the merger of Wayne Enterprises and Queen Consolidated. Bruce Wayne can travel to Star City to finalise the business deal, but actually, he is hunting a violent criminal (Riddler or Two-face) who escaped Gotham prison, both of them could team-up and take him down for good.
Gotham-Arrow Crossover:
