Titans photos reveal the team meeting the Doom Patrol, whom the upcoming fourth episode is named after. With Robin, Starfire, Beast Boy, and Raven having finally gathered, the next episode is set to introduce the other team of misfit superheroes, who will be getting a series of their own in 2019. By the looks of it, they'll have a hand in uncovering the terrifying secret to Rachel Roth/Raven's identity and destiny.
The third episode of Titans picked up after The Family kidnapped Rachel, nearly killing Dawn Granger (Dove) in the process. Starfire, still suffering from amnesia, saves Rachel, fries the Dad in the process, and the two of them move closer to what is presumably the discovery of Rachel's demon overlord father Trigon. Meanwhile Robin, whose childhood enticement into the vigilante life by Bruce Wayne is seen in flashback, catches up with them, as Rachel meets Beast Boy in a roller rink. As Starfire pieces together that Rachel is the key to the "destroyer of worlds," Rachel runs off again. And in the next episode of Titans, the Doom Patrol are on track to put the apocalyptic prophecy together.
The newest Titans photos revealed that Beast Boy caught up with Rachel, and indicated that the two of them, seated around a cheerful looking dinner table, become the Doom Patrol's house guests. It remains to be seen if Robin and Starfire catch up with them before or after the Doom Patrol moves Rachel to a laboratory to examine her - though, in some of the photos, it doesn't appear to be Raven on the examination table. Check out the photos below:
While Elasti-Girl (April Bowlby), Robotman (Brendan Fraser), and Negative Man (Matt Bomer) are clearly shown, The Chief (Timothy Dalton), as well as Cyborg (Jovian Wade) and Crazy Jane (Diane Guerrero) don't appear to have arrived yet. Negative Man appears to be leading the exam as he says, "I can remove whatever is inside you" to Rachel in the trailer for the episode.
With the Doom Patrol, as well as Hawk and Dove being introduced and explored this early on in Titans, it's safe to assume that DC is doing the work of setting up the larger universe with significant crossovers. It's also worth noting that Titans opens with the DC Films intro sequence, which was introduced to the films beginning with Wonder Woman, and that the show has already revealed that Superman exists somewhere in the universe. Unlike the Justice League, which is traditionally made up of the DCU's most decorated and renowned heroes, the Titans and the Doom Patrol are often outcasts brought together out of having nowhere else to go. The main differences between the two groups are age and life experience.
Much like how Buffy The Vampire Slayer was thematically about growing up, while its spinoff Angel explored what it means to be an adult, the dichotomy and potential interplay between the Titans and Doom Patrol has some very lucrative opportunities for rich character development and a very successful new DC world.