to Drawing from his New 52 backstory, Dwayne "The Rock" Johnson's version of Teth-Adam will start out as a slave -- although he isn't sure whether they'll use "face replacement" for the pre- and post-powers version of the character or just use two separate actors.
The other thing he doesn't know? Who will play the titular hero.
“No. I can’t wait to share more casting news by the way," he told MTV. "No, we haven’t picked a Shazam yet, and we have been working on the script. Half the scripts [have] already come in. Fantastic, very excited about it. And what I’m really excited about is — because, again, I’ve lived with this character, and this opportunity for almost 10 years now, so it’s like, in my DNA! I’m like a little kid, and it’s the opportunity to create his journey, but that journey has to start out properly.”
“And starting off properly is him not being a hero,” Johnson added. “That’s got to be earned, so he starts off as a slave. And he’s pissed off, and people are going to pay. But eventually down the line he’ll become an anti-hero.”
Again, that jives with the New 52 iteration of the character...and indeed most of the Geoff Johns-written stories featuring Black Adam, since Johns is such a fan of the character. He's been the chief architect of Black Adam's destiny since JSA.