Ben Affleck
Ben Affleck revealed that Deathstroke will be in “Justice League.” The actor is pictured at the “Suicide Squad” premiere on Aug. 3, 2016 in London. Getty Images

Ben Affleck just dropped a big spoiler about “Justice League.” The actor, who will also direct a standalone “Batman” movie, posted footage on Twitter Monday that clearly shows Deathstroke.

Affleck didn’t post any accompanying text with the clip, but the orange and black mask makes the villain’s identity pretty unmistakable. The video has no sound, but it’s clear that Affleck is filming a monitor on set.

Deathstroke is a major villain in the DC Comics. The killer, also known as Slade Wilson, was created in 1980 by Marv Wolfman and George Perez. He is an assassin with some special skills. After being an exceptionally good fighter in the Army, he was chosen for an experiment that attempted to create super soldiers. He became a metahuman with heightened speed and strength. He isn’t just muscle, though. Being highly intelligent helps make him a real threat.

Unfortunately, he also has some tragic family history. He kept his deadly career path a secret from his wife, Adeline Wilson, so she was enraged when a criminal went after their son. They kidnapped and killed the little boy, and Adeline tried to kill her husband for endangering their son. She shot him, but she only managed to destroy his right eye. It isn’t clear if the movie will keep the backstory, though.

2017’s “Justice League” will feature Deathstroke as the main villain, TheWrap confirms. In the comics, the mercenary faces the Justice League plenty of times. However, he doesn’t often take them on by himself. Deathstroke has joined several teams over the years including the Suicide Squad, Injustice League and Titans. Perhaps Deathstroke isn’t the only villain in the film.

It’s worth noting that the “Justice League” trailer only focused on the heroes. Getting the good guys together is shown to be a challenge, but the clip doesn’t make it clear what threat they’ll face when they finally band together.

“Justice League” will be Slade Wilson’s first live-action movie. The character has appeared in several animated films, and he was recently brought to life by actor Manu Bennett on The CW’s “Arrow.” Producer Mark Guggenheim revealed on Tumblr earlier this year that the character wasn’t returning to the TV show because another DC project was utilizing him.

It isn’t clear who has been cast in the film version of the character. Unlike the Marvel Cinematic Universe, the DC TV shows are not connected to the DC movies. Deathstroke is one of several characters, including Superman and the Flash, who have been on The CW recently but also have counterparts on the big screen.

“Justice League” is set to hit theaters Nov. 17, 2017.