For years Arrow has been leading the charge when it comes to DCTV. It was the show that started a whole multiverse on The CW. Now the live-action world of DCTV is about to get just that much bigger with a Titans series on DC's yet-to-debut streaming platform. Yet while it would seem natural for the Arrowverse and Titans to crossover, there are no plans.
Arrow (and its spinoffs) have hinted at the existence of some of the heroes that will be in Titans. Oliver Queen name-dropped Bruce Wayne in season 6 who is, of course, the mentor to the Titans' leader Dick Grayson. (Actor Brenton Thwaites will be leading the Titans series as Dick.) Oliver has also frequently visited Bludhaven, the home of Dick's grown-up superhero persona Nightwing. This is not even to mention that Arrow had Roy Harper as a part of its supporting cast, while The Flash had Wally West. Both Wally and Roy are founding members of the Teen Titans in the comics. Still one of Arrow's executive producers doesn't see a combined future between the series, at least not right away.
At ACE Comic Con, Arrow co-showrunner Marc Guggenheim was asked about the possibility of Titans and Arrow crossing over, as well as which character might pop up on Titans. Guggenheim responded:
Great question, again, above my pay grade. I will say this, the one thing I’ve learned is ‘never say never.’ I could not begin to tell you how often we say to each other, ‘We never thought any of this was going to happen. We never thought we’d see all these characters. We never thought there’d be a universe.’ So, never say never, but in terms of which characters be on which shows, what’s part of the universe, above my paygrade and probably that’s a good thing.
While maybe disappointing for some, this does seem to fit in with the current status quo for the Arrowverse. Black Lightning will be premiering in 2018 and be paired with The Flash on The CW but there are no plans to connect it to the multiverse that has been created. Black Lightning will exist in its own world.
At the same time, it must be mentioned that plans can change very quickly. This is what Guggenheim points out in his answer. Supergirl originally started as a completely separate series. Now it has been incorporated fully into the Arrowverse, even though it takes place on another Earth.
It seems like Titans, which is preparing to film its first season, will begin in a similar fashion. While there might be references and Easter eggs, it doesn't seem like it will take place on Arrowverse's Earth-1. It's a dim hope but the hope is still there that one day Thwaites' Dick Grayson and Stephen Amell's Oliver Queen will interact on Titans, Arrow or both.
Arrow season 6 airs Thursdays at 9/8c on The CW. Titans will premiere sometime in 2018.
Source: ACE Comic Con