What's The Deal With Sivana?

Every hero needs a villain, and for Shazam! that villain is Dr. Sivana (Mark Strong). In the comics, Sivana is a decrepit mad scientist obsessed with magic. Usually, he doesn't have any powers, though the latest comic reboot gave him the ability to "see" magic. The movie decides to kick it up a notch and really shoots him full of steroids. Sivana has powers on par with Shazam, so question one is how did he get these abilities? Questions two is what does he want them for? Sivana is clearly up to no good, and word on the street is that he has a revamped backstory (which I won't spoil for you here), but it's unclear exactly what his true motives are and what he hopes to accomplish.