Unlike its older "brother," the Marvel Cinematic Universe, and despite DC's boatload of superheroes, the list of DC Extended Universe characters is still relatively slim - after all, only a handful of DCEU films have been released. However, that doesn't mean that the folks at Warner Brothers haven't been able to cram a few obscure characters into the DC films via some clever DCEU Easter eggs. In other words, there may be more classic characters in DC movies than fans realize at first glance.
DC Comics have been around since the '30s, and that means the people behind the DCEU have almost a century of publishing history to draw from. While all the most prominent characters, like Batman, Superman, and Wonder Woman, have all received their time in the spotlight, it turns out that some lesser lights like Apache Chief, Jimmy Olsen, and the KGBeast have also made more subtle appearances. These cameos add color and depth to the DCEU and make for a more rewarding viewing experience for DC superfans.
Jimmy Olsen is a classic "boy sidekick" type of character best known for his friendship with the Man of Steel. As one of Clark Kent's most tenured allies, Olsen was an obvious candidate for a cameo appearance in Batman v Superman: Dawn of Justice. However, few could have predicted that Olsen would appear for a matter of minutes in the DCEU before being cruelly executed.
He's the photojournalist traveling with Lois Lane at the beginning of the film, but he's also discovered to be a CIA spy - which leads to his demise.see more on Jimmy Olsen
After the box office disaster that was 2011's Green Lantern, it suprised fans that Justice League went ahead and confirmed the existence of the Lantern Corps in the DCEU. In the epic and sprawling flashback battle scene that provides exposition on Steppenwolf, several factions can be seen amidst the fighting, including Atlanteans, Amazons, Greek gods, and at least one Green Lantern.
Eagle-eyed and well-read fans have even figured out the likely identity of the Lantern in question: Yalan Gur, a relatively obscure ancient member of the Corps.see more on Green Lantern
Many fans speculated that Chief, a fan favorite character from Wonder Woman, was meant to be an adaptation of Apache Chief, a size-changing hero from the Super Friends cartoon. However, Chief initially introduces himself to Diana in his native Blackfoot language, and in that bit of dialogue, he refers to himself as "Napi," an entity that actor Eugene Brave Rock describes as a "Blackfoot culture hero and Demi-god."
That means that the character is actually closer to an adaptation of a much more obscure DC Comics hero: Super Chief. In any case, this mythical origin makes it entirely possible that Chief could show up in future Wonder Woman sequels even though they take place over a century after the original film.see more on Super-Chief
Although Oswald Cobblepot, the Penguin, has yet to appear in the DCEU, sticking to TV's Gotham instead, audiences know that the character did exist at one point in the DCEU Batman's past. That's because, with the newly formed Justice League facing an invasion of Parademons, Alfred Pennyworth wryly observes: "One misses the days when one's biggest concerns were exploding wind-up penguins."
There's only one Bat-villain that employs exploding wind-up penguins, and that's Oswald Cobblepot.see more on The Penguin