There's a big reason why Dwayne "The Rock" Johnson chose Black Adam over Shazam and it's not just so he can show off how 'roided he is. Black Adam is a complex character-- sometimes even more so than his goody-two-shoes counterpart, Shazam. While Adam's story has changed many times in the DC comic books, he still remains one of the most interesting supervillains ever in their roster of baddies.
At times, he even tiptoes the line between anti-hero and supervillain. This makes him kind of like the Doctor Doom of DC. From his humble and oppressed beginning as a slave (in the new 52 version, which is what Dwayne Johnson's Adam will follow), Black Adam rose up; he became a liberator, murderer, superhero, and supervillain all interchangeably. So, in order to understand Black Adam's motivations, we have laid out some of his most evil deeds alongside his most heroic ones. Here are the two dimensions of Black Adam.
10 WOULD DO ANYTHING FOR HIS WIFE (HEROIC)
Beware of supervillains who have a family, and Black Adam just happens to be a family man... well, happened to be anyway. His family actually died in all his origin stories. It was his second wife, Isis (formerly Adriana Tomez) who meant so much to Adam that he was willing to anything for her. It's too bad she died.
Adam, not giving up on Isis, sought for ways to resurrect her. One of those was embarking on a perilous journey to rebuild Isis' amulet, the key to resurrecting her. That would have been easy if only Adam didn't lose the powers bestowed upon him by the gods. Even without them, Adam still braved the Himalayas and managed to slay a Yeti as a human.
9 IS FRIENDS WITH SINESTRO (EVIL)
It's not uncommon to see supervillains banding together in their own dark version of the Justice League. After all, they have common enemies. However, not many of them become friends afterward since they're all rogues. Not Adam and Sinestro, though. The two powerful members of their own respective rogues' gallery are tighter than two peas in a pod... meaning they're best buddies.
While that sounds fun, it's actually evil and such a partnership made the two unstoppable. Together, with a more powerful Sinestro Corps in tow, they took on the Crime Syndicate and won. Afterward, Adam became an honorary member of the Sinestro Corps and has since become one of the Green Lanterns' enemy's trusted friends. They even gave Adam a Yellow Lantern ring.
8 LIBERATED KAHNDAQ AND HIS PEOPLE (HEROIC)
Black Adam, being a slave in the New 52 version knew the horrors his own people endured at the hands of their oppressors in ancient Kahndaq. Such trauma and ordeal is not something one forgets, even when they rise to power. Hence, when Adam was bestowed the power of the Egyptian gods' version of S.H.A.Z.A.M. (Shu, Heru, Amon, Zehuti, Aton, Mehen), he took it upon himself to free "his people"... even when thousands of years have passed.
To Adam, memories of Kahndaq's dictators were still fresh. Even when new and more modern faces replaced monarchs, it was more or less the same oppression in Adam's eyes. So he waged war on modern Kahndaq's armies and authorities and took over the government. Adam made Kahndaq his own, just as he had planned after getting his powers in back in ancient times.
7 A TYRANT THROUGH AND THROUGH (EVIL)
Despite liberating his people and giving them better opportunities to be alive when compared to their former oppressors, Adam was still a tyrannical ruler. He was somewhat fair and rewards those who are loyal to him. However, he still believes that his own plans and convenience are the better priority. He'll even kill those who annoy him without any remorse or hesitation.
To Black Adam, the ends justify the means. He's shown this even when he had to massacre the Kahndaqi soldiers who stood against him when he took over. In fact, Adam at least the old one before the New 52 reboot, showed no qualms about cannibalizing his own men to stay alive during his trek to the Himalayas in order to resurrect his dead wife, Isis.
6 JOINED THE JSA (HEROIC)
Black Adam isn't exactly the most dependable anti-hero in DC. At one point, he has fought for the good guys. In JSA #21 Black Adam joined the Justice Society of America and he was quite humble and eager about it. As such, the annals of Justice Society of America forever now has Black Adam in its roster or former members, if you will.
It was a fruitful allegiance too. With Black Adam's help, the JSA was able to take down the Injustice Society. It did take a bit of guile on Adam's part since he also joined the Injustice Society around the same time he joined the JSA. His tenure at the JSA didn't last long since they found out about his Kahndaq conquest with the help of the JSA acolytes nonetheless.
5 SHAZAM'S SWORN ENEMY (EVIL)
Let's not forget the most obvious reason why Black Adam is still a bad guy: Shazam or Billy Batson. Supposedly, Batson was to be the spiritual successor of Black Adam after the latter pulled a 180-degree turn against the wizards who hand out the S.H.A.Z.A.M. powers like they were carnival tickets.
In the New 52 version of both Adam and Shazam, Adam also desired Shazam's power. He even went as far as trying to murder Billy's family just to get it. Black Adam also kept trying to crack open poor young and clueless Billy Batson just to take his powers. To make matters worse, not many could stop Black Adam in trying since he can pretty much go toe-to-toe with Superman. He could probably even defeat the Man of Steel.
4 SAVED HIS NEPHEW (HEROIC)
How Geoff Johns reimagined Black Adam's story was nothing short of compelling. They gave an old supervillain another dimension and even set him up with an anti-hero template. Black Adam went from a prince to a mere Kahndaq slave when the New 52 reboot landed. His origin story overhaul gave him a more heroic start. The slave, named Adam was left with only his nephew, Aman, as a family.
Adam actually saved Aman from Kahndaqi guards during a siege. This left Adam mortally wounded. Still, Aman came back for his uncle. The two of them escaped only to be teleported to a council of the wizard, Shazam (the one who bestows power). It was to Aman they gave the power of the gods since they recognize Adam's nephew as a good ruler who would restore peace to the world. However...
3 KILLED HIS NEPHEW (EVIL)
Adam's whole family, save for Aman whom he was able to save, was slaughtered by the Kahndaqi authorities. This left Adam vengeful. So, when Aman asked his uncle to help him bring peace to the world and to Kahndaq, Adam rejected the idea. Adam wanted nothing but revenge against their oppressors for killing his family and everyone else's in Kahndaq.
So, upon the act of transforming and just as Aman yelled "Shazam," Adam killed him. In doing so, he also stole the powers of the gods for himself. As it turned out, Adam didn't even need the power of the gods to corrupt himself. He already had that twisted mentality even before he became powerful.
2 DEFEATED ULTRAMAN (HEROIC)
Ultraman (Kal-Il) is the Earth-3 variant of Superman. He's pretty much the same as the omnipotent Kryptonian, except he's nowhere near as kind as Superman. In fact, Ultraman killed the Kents and even took over Earth-3. He then set his sights upon Prime Earth and there, he became nigh unstoppable, no one could defeat him, no superhero at least.
Then came Adam and the Sinestro Corps who were also concerned with Ultraman's superiority. Even so, Black Adam proved to be no match against Ultraman. He had to flee and recover from having his jaw broken by the evil Kryptonian clone. During their second fight, Adam brought along Sinestro and they moved the Earth's moon, causing the rays of the sun to harm and weaken Ultraman. Through this, Black Adam defeated Ultraman and saved the Earth, something not even the Justice League could do.
1 STARTED WORLD WAR III (EVIL)
So, Black Adam once saved the world, that makes him an anti-hero now, right? Maybe... not. He also began World War III, which isn't much different than trying to destroy the world. Adam's lust for war began when the Four Horsemen of Apokolips planned to assassinate him and his wife, Isis. Isis died as a result but in her dying words, she told Adam to avenge her.
So, in Black Adam fashion, he overdid it. He not only trashed two of the Four Horsemen, but he also catalyzed World War III by committing a rage-induced genocide against the two million residents of the nation of Bialya where one of the Horsemen hid. This started World War III where he managed to defeat China's own superhero cohort as well as the Justice Society and the Teen Titans. Thankfully, Shazam and Zatanna managed to stop Black Adam and even temporarily stripped him of his powers.