Doctor Sivana is one of the original villains from the Shazam comics, so to see him in this story isn't surprising. In this story, he's studying an ancient ruin which mysteriously electrifies his right eye, creating the shape of a lightning bolt. This eye can see the true nature of people, which guides him into seeing the seven deadly sins who were roaming the earth (long story). He works with the sins to take over certain humans and commit crimes, paving the way for black Adam.