We're only four movies in, but there's already been a plethora of wild and interesting characters introduced in the DCEU. From heroes to villains, there have been some familiar and not-so-familiar names brought to the forefront of this blockbuster franchise.

Naturally, when Justice League is released later this year, there will be even more individuals added to this ever-growing roster. That said, the DCEU is currently much larger than what we think it is and several superheroes and villains have already been snuck in without us even realizing it. While some of them have appeared in promotional material for the respective film, others have actually popped up on the screen for us to see.

Now, we're not talking about the likes of Jason Todd/Robin and Jimmy Olsen, whom everyone is aware about already. We're talking about those hidden gems that longtime fans will spot and question if there's more to something than meets the eye (hint: there is).

With that out of the way, here are the 8 Superheroes (and 7 Villains) You Didn't Know Were Already In The DCEU.

Superhero: Supergirl

Supergirl Breaker of Chains

No, we're not talking about Melissa Benoist's Supergirl TV series; we're talking about an actual DCEU-exclusive Supergirl. Interestingly enough, there have already been two hints that Kara Zor-El exists in this universe.

The first is in the official Man of Steel prequel comic book that shows Kara's arrival on Earth. Her origin differs slightly from the one we're more familiar with and features a host of other Kryptonian characters as well. It's an entertaining read and certainly fits right into the world created by Zack Snyder.

The second suggestion of her presence is actually in the Man of Steel film. When Clark Kent explores the Fortress of Solitude for the first time, he comes across pods containing preserved life forms, but one of the pods is mysteriously open. It's highly likely that this was Kara's pod.

Villain: KGBeast

Anatoli Knyazev aka KGBeast in Batman v Superman

KGBeast might look like an inferior Bane in the source material, but his first cinematic iteration, as portrayed by Callan Mulvey, looked far more snazzier. Using his real name, Anatoli Knyazev, in Batman v Superman: Dawn of Justice and not wearing a mask or prosthetic gun, the villain served as Lex Luthor's main thug in the movie.

While many people believe that Batman killed him in the infamous warehouse scene, we think his burning will actually be used to factor in his prosthetic gun and need for a mask at a later stage. Remember, no one ever stays dead in the comic book world...

The Beast might not be a first-rate villain, but he certainly works well as a secondary antagonist or henchman. Here's hoping he makes another DCEU appearance somewhere down the line.

Superhero: Jenet Klyburn

Batman V Superman Ultimate Jena Malone Role

While Jenet Klyburn might not be a superhero in the strictest sense of the word, she does act as a director of S.T.A.R. Labs and has assisted the likes of Superman and the Teen Titans when they've needed her.

Unfortunately, her appearance in the DCEU was so under the radar that you'd only notice it if you bought Batman v Superman: Ultimate Edition and paid close attention to the new scenes.

Played by Jena Malone, whom everyone was convinced was set to be Barbara Gordon or Carrie Kelley, Klyburn helps Lois Lane inspect the prototype bullet she discovered during the battle in Nairomi. In many ways, it's the quintessential role for the character, as she does exactly what we'd expect her to do: help.

That said, it's looking unlikely that we'll ever see Klyburn in this universe again. If her brief few minutes on screen were cut before, we can't imagine her receiving a bigger role in the future.

Villain: Riddler

Riddler Batman Best Comic Villain

Riddle us this, did you spot the enigmatic one's Easter egg in Batman v Superman: Dawn of Justice?

Naturally, Batman's riddle-loving foe would choose a more intelligent introduction than a mere walk-on cameo. For those with a sharp eye, though, his trademark question mark is seen as the Dark Knight prepares to do battle with Superman.

While the question mark acts as an indication of the villain's presence in this world, it also serves as terrific tribute to the Arkham games and the Riddler trophies.

It's been 22 years since we witnessed Jim Carrey's portrayal of the Riddler in 1995's Batman Forever, so it's definitely about time that the character makes a comeback to the DC movie world. Perhaps he'll have a major part to play in Matt Reeves' The Batman?

Superhero: Orana

From the likes of Artemis to Antiope, many Amazon warriors made their bow in Patty Jenkins' Wonder Woman.

However, there was one Amazon whom many of us missed: Orana. Played by Mayling Ng, Orana doesn't have a major role in the film, yet she's part of the battle against the Germans on the beach of Themyscira.

In the comics, the character of Orana was a formidable fighter who challenged and defeated Diana for the title of Wonder Woman. Unfortunately, much like her appearance in the film, she dies rather soon and allows Diana to reclaim her title.

Despite dead characters often making miraculous resurrections in the various comic book reboots, Orana has stayed as dead as a doorknob for many years. That's why it was such a surprise for longtime fans to see her pop up in Jenkins' film.

Villain: Penguin

While Josh Gad has been teasing the internet that he might be portraying Oswald Cobblepot in the DCEU, we've already seen confirmation that the Penguin is a current member of Batman's rogues' gallery. In fact, he's also listed as the owner of the fabled Iceberg Lounge, which can be found on Gotham City's waterfront.

In Time Out Shortlist Gotham and Metropolis, a two-part book that was released to promote Batman v Superman, there's mention of how Oswald opened the club, where it's situated, its phone number, and even its fictional website address (iceberglounge.got).

If you pay close attention to the Comic-Con Justice League trailer as well, you'll hear Alfred say to Bruce, "one misses the days when one's biggest concerns were exploding, wind-up penguins." Obviously it's a reference to Batman Returns, but also a tip of the hat to the old Penguin himself.

Superhero: Green Lanterns

Green Lantern Corps Comic

It's safe to say that we will see at least one Green Lantern in Justice League, because at this point, it would be disappointing if we didn't. Whether it'll be John Stewart or Hal Jordan -- or others as recent rumors suggest -- we'll have to wait and see.

Nonetheless, we already know they exist in this world, due to the Green Lantern Corps announcement and Steppenwolf casually name-dropping them in the latest Justice League trailer.

While John and Hal are all but confirmed for the DCEU, it'll be intriguing to see which other Lanterns make the cut. Could we be seeing the newest Lanterns, Jessica Cruz and Simon Baz, make an appearance as well? Say what you will about the failed Green Lantern film, but it did contain a wide range of popular Lanterns, so hopefully this universe follows suit.

Villain: Conduit

This was a blink-and-you'll-miss-it moment in Man of Steel. In one of the flashback scenes, Clark sits in the truck, reading and waiting for his dad. Kenny Braverman and some of his friends yank the Boy of Steel out of the vehicle and throw him to the floor.

They taunt and threaten him, being typical high-school jocks. As Clark is about to lose his cool and punch them to another galaxy, Pa Kent returns and the boys scamper away.

While he might seem like any other jock bully, Kenny is actually known for his history with Clark in Smallville and for going on to become the supervillain known as Conduit.

He might not be considered a premium antagonist for Supes, but his kryptonite-based energy manipulation abilities do mean that he can give Clark more than a few headaches when he's around.

Superhero: Booster Gold

Booster Gold smirking in a DC comic.

Even though Greg Berlanti has suggested that a Booster Gold film might exist outside of the DCEU realm, there's an Easter egg referencing the time-traveling character in Man of Steel, so it would make sense for him to be connected to this universe in some way.

Granted, it's only momentary, but it's still fairly significant. As General Zod and Superman tear each other to pieces, look towards the Metropolis backdrop and see if you can spot a billboard with the familiar logo of Blaze Comics on it.

If you didn't know, Blaze Comics is a fictional publishing company in the DC universe that was responsible for Booster Gold comics. It was one of the many forms of merchandising that Booster used so he could have a comfortable living from his self-promotional endeavors.

Villain: Emmett Vale

When Zack Snyder first planned Batman v Superman's villain, an early favorite was Metallo. Ultimately, Snyder went in a different direction and cut the antagonist from the script altogether, but that doesn't mean he didn't throw in a cheeky reference, though.

Look closely and you'll see that one of Lex Luthor's scientists in the film is Emmet Vale (portrayed by Ralph Lister and with only one T here), the man better known for creating Metallo. He doesn't have a crucial part in the story, but it's enough to show us that he has knowledge of Kryptonians, which is rather significant to his character's history.

For those who might not be familiar with John Corben's transformation into Metallo, Corben was a critically injured criminal who looked like he was set to kick the bucket. However, his life was saved by Vale who transplanted Corben's brain in a robotic body that was powered by a kryptonite heart. Sounds rather painful.

Superhero: Blue Beetle

Ted Kord Blue Beetle from DC Comics

Part of the promo for Batman v Superman included a fictional WIRED interview with Lex Luthor. While it was a nifty PR move, the interview also provided a few more tidbits about the DCEU than we initial thought.

Looking at the 2015 defense R&D budget diagram, a familiar organization pops up as a top spender: Kord Industries. Furthermore, the article states that Kord has been in the defense field for over two decades now.

The big chief of Kord is undoubtedly Ted Kord, AKA the second Blue Beetle. Whether we'll see him suit up as the hero, or hand over the mantle to Jaime Reyes much like Hank Pym did to Scott Lang in Marvel's Ant-Man, is still to be seen. Nonetheless, Kord is a part of this universe, so we should expect to meet him at some point.

Villain: Star Sapphire

Did you spot a United States Air Force officer named Carrie Farris (played by Christina Wren) in Man of Steel and Batman v Superman? If so, you should know that she's an allusion to Carol Ferris, who's better known for being Hal Jordan's longtime love interest.

Additionally, Ferris is also known for becoming the second Star Sapphire. The premise for the character is as follows: The Zamarons are an immortal alien species of warrior women who have an ancient tradition of choosing physically identical mortals to serve as a host body for their queen.

This host then turns into Star Sapphire, who is able to use a crystal that grants her similar powers to that of the Green Lantern's power ring.

For many years, Star Sapphire served as an antagonist for the Green Lantern; however, the character's various incarnations flirted with heroism on many occasions as well.

Superhero: Green Arrow

In the same WIRED article that mentions Kord Industries, there's another name that DC Comics fans should immediately recognize: Queen Industries. Naturally, this is a reference to the one and only Oliver Queen, AKA the Green Arrow.

What's interesting about this particular allusion is that it also offers us some insight into Ollie's public persona. In the summary of Queen Industries, the CEO is mentioned as being aloof, often absent, and looking to pull out of military contracts altogether. That's a sure sign that Ollie is already the Emerald Archer and out saving his city.

Considering the popularity of the TV series Arrow, it's only a matter of time before we see this character in the DCEU. Hopefully, though, Warner Bros. and DC have called up Charlie Hunnam to discuss the role already, since we all know he's the only logical choice here.

Villain: Firefly

Firefly DC Comics on Gotham

Prior to the release of Batman v Superman, there were five prequel comic books released by DC Comics and Dr. Pepper. In issue #1, the Batman book, the Dark Knight's brutality is explored and we're given a bit more context as to why he likes to break kneecaps and crush skulls in the DCEU.

It's in this issue that we see the Caped Crusader stop Firefly from blowing up a building. When the hero intervenes, the pyromaniac villain attempts to burn him, but the Bat uses all his tricks and resources to stay cool and lay an almighty beatdown on his fiery foe.

While he doesn't murder Firefly, Batman pummels his adversary in such a way that he destroys his suit and knocks the hell out of him. Well, we're sure he'll walk again at some point - maybe with a limp though.

Superhero: Zatanna

Zatanna - Underrated Female Superheroes

Annataz si ni eht UECD-- for those of you who didn't catch the reference, everyone's favorite backwards-magic-loving Mistress of Magic is in the DC universe.

While her name was brought up for the Justice League Dark film, which seems to be in a constant state of limbo, there's also another mention of her in Time Out Shortlist Gotham and Metropolis.

There are two confirmations of her existence in this book. First, her father Zatara's magic shop is advertised, seemingly confirming his appearance in the DCEU as well. The second is a mention that Zatanna is a frequent performer at Gotham's Club Vesuvius.

If Justice League Dark does eventually happen, you can be certain that she'll be front and center of it. If not, however, it would be interesting to see if Warner Bros. and DC decide to bring her in as a love interest for Bruce Wayne in another movie.

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Can you think of any other characters that are already in the DCEU? Sound off in the comments section!