There's plenty to dissect when it comes to Justice League, but one of the bigger mysteries gets a definitive answer by the film's end, and it has to do with everyone's favorite assassin Deathstroke.
Spoilers incoming for Justice League, so if you haven't seen the movie yet you've been warned.
Deathstroke's involvement with Justice League and the greater DC cinematic universe, in general, has been in question for some time. Test footage was revealed early on of actor Joe Manganiello in full costume, but it wasn't known where he would eventually show up. The answer turns out to be Justice League's first after credits sequence.
The sequence starts off at Arkham Asylum, as the Guards direct the prisoners to their regular duties. A prisoner is turned away from the camera, sporting a bald head similar to Lex Luthor's. He isn't moving though, so the guard issues a few more commands. He doesn't budge, so the guard approaches him and turns him around, revealing a prisoner who is most definitely not Luthor.
The scene flashes over to a yacht in the ocean, with another smaller boat approaching it. As the camera pans closer you can see an armored figure walking onto the yacht, which turns out to be Deathstroke in all his glory. He approaches the main figure on the yacht, which is revealed to be Lex Luthor. Luthor has a proposition for Deathstroke, and that's when Deathstroke removes his helmet to reveal a gray-haired and eye patch wearing Manganiello.
That's a pretty fantastic moment to be sure, but Luthor makes it even better when he teases that the two should "start a League of our own."
Yeah, suffice it to say that scene crushed, and it appears to be the beginning of the heralded Legion of Doom. Certainly not a bad way to kick things off.
Deathstroke was originally intended to be a part of The Batman solo film, but that project has undergone plenty of changes in the months since that was announced, including a change in directors and a total overhaul of the script. Since then it has been revealed that a Deathstroke solo film is in the early discussions phase, but that will most likely largely depend on where the villain surfaces next. If it is Justice League 2, it might be awhile until we see a solo film
You can see the scene for yourself as Justice League is in theaters now.