Back when comic books could be picked up for a dime at every newspaper stand on the block, the superhero formerly known as Captain Marvel — now Shazam — reigned supreme. He even outsold Superman! This April, Shazam makes his long-awaited big screen debut, with one of his oldest nemeses in tow: Dr. Sivana, played by Mark Strong.

Here’s everything you need to know about Dr. Sivana in the upcoming movie, Shazam!

Many Versions, Evil All the Same

One big thing you need to know about Dr. Sivana within the Shazam family of comics is that there are several differing interpretations of the character, but some traits remain consistent. As his name implies, Sivana is a brilliant scientist (in what field? depends who’s writing) who always sets out to do good, but becomes morally twisted and consequently resorts to classic, old school comic book villainy.

He’s also physically what you expect a mad scientist type to be: Bald, hunched, kinda small. He’s in many ways the polar opposite of Shazam, an orphan kid named Billy Batson endowed with the powers of a god.

Dr. Sivana first appeared alongside Captain Marvel (renamed Shazam in 2011) in Whiz Comics #2 in 1940. After Black Adam, he immediately became one of Shazam’s most famous arch-rivals, always trying to use science to thwart the magic wielded by Shazam. Also, he moves to Venus for awhile.

Cover of 'Whiz Comics' #68, featuring both Captain Marvel (now Shazam) and Dr. Sivana. DC Comics

In 1985, when DC rebooted its continuity, Dr. Sivana was reintroduced in Shazam! The New Beginning, this time with two children of his own, and was made Billy Batson’s step-uncle. In a 1994 graphic novel, The Power of Shazam!, Sivana was rebooted again, this time as a powerful CEO in addition to his brilliant mind.

Dr. Sivana kept showing up in various storylines, including 52 and Final Crisis, before he was rebooted yet again in 2012 shortly after DC’s “New 52” began. In several interconnected issues of Justice League written by Geoff Johns (later collected into its own volume, titled Shazam!), Dr. Sivana surfaces as a more physically imposing rogue scientist who seeks the legend of Black Adam to save his family. When Dr. Sivana resurrects Black Adam, the power surge blinds Sivana in his right eye, allowing him to “see” magic.

When Black Adam goes back on their agreement, Dr. Sivana winds up teaming with Mister Mind — another old villain of Shazam’s. That’s where the comic ends, although DC just recently began publishing the ongoing sequel series, Shazam!, again written by Geoff Johns.

Science Over Magic

Another important distinction with Dr. Sivana is that he historically favors science over magic, the very thing that empowers Billy Batson to become Shazam. Whereas Shazam is youthful, reckless, and just a little over-energetic, Sivana is old, cold and calculated.

Sivana doesn’t have any real powers. Like many comic book villains, he relies on his genius intellect over any kind of raw strength. Although as the New 52 continuity showed, Sivana can now “see” magic in his scarred right eye, a trait that the film seems to be adapting.

Dr. Sivana in 'Shazam!,' written by Geoff Johns and illustrated by Gary Frank. DC Comics

Sivana on the Silver Screen

The movie Shazam! is taking a lot of big cues from Johns’ 2012 reboot. It’s also giving him some cool abilities, perhaps obtained from Dr. Sivana’s relic hunting and messing with ancient things he shouldn’t mess with.

“He gets to fly, he can create electric fields in his hands, and fire electricity,” said actor Mark Strong in a set interview (via Den of Geek). “He’s much more robust and much more powerful.”

Costume designer Leah Butler added, “He’s tall, he stands well, he’s very strong and different than the slouched over mad scientist that he has been in the past.”

Mark Strong as "Dr. Sivana" in 'Shazam!' (2019). Warner Bros. Pictures

The film is also taking inspiration from The Power of Shazam! with a tycoon Sivana.

“In looking at different ideas for him, I’ve actually come across some little tidbits throughout the history of him being a wealthy tycoon,” Butler said. “He has his own company in our movie, Sivana Industries. He’s wealthy. He feels like he’s better than everyone else. He’s almost royal in his own mind.”

Finally, one major aspect of Black Adam is being adapted into Dr. Sivana. In Johns’ reboot, Black Adam awakes in the modern world and is horrified to find that the great power he seeks has been given to a misfit child. Mark Strong’s Sivana is taking on that jealousy for the movie.

“[Sivana] can’t understand that the Wizard has chosen this boy as his champion,” Strong said. “The wizard has chosen a boy, and he realizes that obviously that boy manifests himself into the Zachary version of Shazam. To him it’s a source of total incomprehension why this boy should have been chosen over him.”

Shazam! flies into theaters on April 5, 2019.