The Justice League has come to Titans, confirming even move major superheroes for the world of the DC Universe streaming show. While the show started slow, focusing on the individual Titans as they slowly came together, it also gradually built out the larger, fully formed DC universe that the Titans live in.
The world started with the expected things, name-dropping Batman and the Joker, Robin sneaking around Wayne Manor with Bruce and Alfred always just out of sight. Dick has a host of names in his phone's contact list, confirming even more heroes, then in came Hawk and Dove, along with a Superman Easter egg, suggesting the Man of Steel may also exist.
The most recent episode, 'Donna Troy', opens with a young Dick Grayson hanging out with young Donna Troy in Wayne Manor while Wonder Woman and Batman talk downstairs for a "Justice League thing." While we don't see any of the League, or hear of anyone other than the Dark Knight or the Amazon, the confirmation that the League exists is a big deal. Without a full membership roster, we can know of at least 3 characters that would be members, but we'll definitely be on the lookout now to see what other Leaguers could exist in the world of Titans.
We've known Batan is in Titans since the very first episode. The show has very much stuck to DC canon in the parts of Batman we have seen from his Robins, both Dick Grayson and Jason Todd, to the Batcave and Batmobile, but this version of Batman also embraces a number of Batan's crueler aspects, which is a big factor in why Dick left him and eventually quit being Robin. Even so, Batman is the world's greatest vigilante, and we've already had some other impressive examples to compare him to.
We haven't seen Wonder Woman, but through dialogue from Donna Troy, AKA Wonder Girl, we actually got a significant portion of Diana Prince's traditional canon confirmed. Naturally, she's a Amazon who comes from the island of Themyscira, where she was raised and educated by her Amazonian sisters before joining the world of man. Donna contrasts Wonder Woman against Batman by saying he punishes the guilty, while Diana protects the innocent. All in all, what we know about Wonder Woman seems to do the character proud.
Superman is the most interesting addition here because the only tease he's seen is from his symbol appearing on a t-shirt worn by Dawn Granger, AKA Dove. Now that we have the confirmation of the Justice League, Batman, and Wonder Woman, it's hard to assume that Superman is simply a fictional character popular enough to inspire merchandise like Dawn's shirt.
If we have an Amazon like Wonder Woman, there's no reason we can't also have Superman, although that raises larger questions about why nobody has mentioned him yet, as he'd presumably be a much bigger deal. Especially if Batman is a household name. It may not be enough to outright confirm he exists, but it's certainly more likely than not.
Who Else Could Be in Titans' Justice League?
The only other heroes confirmed in the show so far are Hawk, Dove, and the members of Doom Patrol. While they've all worked with the League at one point or another, none of them are have actually been Justice League members, other than Cyborg, who won't be introduced until the Doom Patrol show (although he may not actually join the League - he's more likely to be a part of Doom Patrol and the Titans first).
With Starfire finally confirmed to be an alien, the possibility of Green Lantern, Martian Manhunter, and Hawkgirl and Hawk Man. Otherwise, fans will have their eyes out for any mentions of The Flash, especially with Wally West missing from the Titans team.