WARNING: The following article contains major spoilers for Shazam!, in theaters now.

The pure joy many critics and fans have felt watching Shazam! should serve as affirmation that Warner Bros. has shed the grim-and-gritty tone that so defined the first films of the so-called DC Extended Universe. That doesn't mean the shared universe has any intention of forgetting those early installments, however, as Shazam! is chock-full of references to those depictions of Batman and Superman.

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Rest assured, those nods are more than mere fan service. The references to Superman in particular are important to the story of Billy Batson. It might seem as though Shazam! aimed to introduce a worthy contender to replace the Man of Steel in the franchise, and while Batson is absolutely capable of filling that role, the best way would be for Superman and Shazam to continue to co-exist. That's because Shazam and the DCEU need Superman in order to grow.

The DCEU's depiction of the Last Son of Krypton is the subject of argument among fans, many of whom were disappointed that, unlike his comic book counterpart, this Superman isn't the hopeful, compassionate hero everyone hoped to see, beginning with the contentious ending to Man of Steel, in which he snaps General Zod's neck.

Perception of the character remained largely unchanged through Batman v Superman: Dawn of Justice, and only improved with the release of Justice League, because, despite that Superman appeared to be an antagonist in the moments following his resurrection, he soon fought alongside the heroes with a sense of lightheartedness. He was cracking jokes, racing The Flash and defeating bad guys with the kind of gentle enjoyment fans enjoyed seeing in the comics. It was some much-needed course correction, but Clark Kent's journey is incomplete.

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Regardless of the Man of Steel's current cinematic reputation, Shazam! refused to hold back on references to the superhero, beginning with Freddy Freeman's memorabilia collection, which includes abullet that bounced off the chest of Superman.

It doesn't stop there. While Billy explores his powers, he and Freddy make references, and comparisons, to Superman. When Billy learned how to fly, one of the first things he tried was the classic Superman pose. Freddy made a more direct reference during the training montage when Shazam attempts to "leap tall buildings in a single bound," which results in the fledgling hero crashing into a skyscraper.

Of course, we have to mention the cameo at the end of the film. It wasn't Henry Cavill in the role (we don't even see his face), but it was definitely significant, as it linked Shazam to Superman. All of those references made it crystal clear that Billy Batson looks up to Superman as a role model, and why shouldn't he? In fact, should Warner Bros. continue to develop its shared universe, the hero would be the perfect mentor for Billy Batson.

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Superman has always been about hope. His strength and power remind us that good overcomes evil. In the early 2000s, his insignia was even confirmed to be a literal symbol for hope on Krypton, something the DCEU didn't really demonstrate until Justice League.

Regardless, it's clear Kal-El has grown from the reckless Kryptonian who wrecked a rude bar patron's truck to the optimistic hero who understands and forgives Batman for everything he did in Dawn of Justice. Now is the time for Superman to pass on what he's learned, and to prove he's a champion of hope by shaping a younger superhero.

Of all superheroes introduced to date in the DCEU, Billy Batson would be a fitting student. Let's not forget that, despite wielding the power of the gods, he's still just an impressionable 14-year-old boy. He's come a long way on his own, and found a family in Shazam!, but he -- and most of that family -- still needs guidance as a superhero, something his foster parents aren't really equipped to provide.

That kind of a relationship between Superman and Shazam would benefit both of their stories. We know that, because Superman acted as something of a mentor to Billy Batson in the comics, starting with Superman/Shazam: First Thunder, written by Judd Winnick and illustrated by Joshua Middleton. It worked there, and it would work on film as well, even if the DCEU's version of Superman is still slightly darker. They would balance each other out.

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The new avenues of exploration a mentor/student dynamic opens for each character were made clear with Spider-Man: Homecoming, which featured two popular characters and developed them both through those roles. Iron Man became more a father figure, while Spider-Man learned how to stand on his own. The same depth of discovery can be accomplished with Superman and Shazam.

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However much sense it may make for both characters, we aren't likely to see Superman become a mentor on the big screen anytime soon. That's partly because Warner Bros. is veering away from a cohesive continuity between films, and instead focusing on more standalone stories like Wonder Woman and Aquaman.

But when the DCEU is ready for another superhero team-up, we hope Superman and Shazam are reunited, more fully this time. They seem to need each other.

Directed by David F. Sandberg, Shazam! stars Asher Angel as Billy Batson, Zachary Levi as Shazam, Mark Strong as Dr. Thaddeus Sivana, Djimon Hounsou as the ancient wizard Shazam, Grace Fulton as Mary Bromfield, Jack Dylan Grazer as Frederick “Freddy” Freeman, Ian Chen as Eugene Choi, Jovan Armand as Pedro Peña, Faithe Herman as Darla Dudley, Cooper Andrews as Victor Vásquez and Marta Milans as Rosa Vásquez. The film is in theaters now.