You'll be hard-pressed to find a fan of Avatar: The Last Airbender or The Legend of Korra that doesn't believe the series is one of the best shows to ever hit the small screen, animated or not. But the popularity of the Avatar world isn't just from the show's style, humor or story, it's from just how darn deep its lore and world-building goes. The Avatar universe spans an enormous segment of time, from the origin of the very first Avatar (a master of all four elements: air, earth, water, fire) in The Legend of Korra to the ones that truly had to face themselves to overcome adversity and evil. At face value, these are children's adventure shows, fit for Saturday morning consumption. But sit down and watch more than a few minutes and you'll find a geo-political epic, packed with emotional character development and some hefty plot points that you'll be surprised to see in a "kid's program." Seriously, this series is just a couple of steps shy of Game of Thrones.

But there's a lot fans of the Avatar universe might not know. Sure, there's the bits and pieces of story that you'll get after a few re-watches of either Avatar or Korra, but there's so much more behind the scenes, things that have captivated fans long after either series has ceased airing. With plans for a live-action Netflix re-telling of The Last Airbender in the works, let's take a look at 20 things fans never knew about the world of Avatar, and no, not the blue people.

20 TOPH WAS ORIGINALLY MALE

Toph from Avatar the Last Airbender bending

Believe it or not, the greatest Earthbender to ever live, Toph Beifong, was actually planned to be a teenage boy in Avatar: The Last Airbender. Airbender and The Dragon Prince writer Aaron Ehasz championed the concept of Toph being a young girl who would show up some of the toughest, burliest Earthbenders in the Earth Kingdom, and he eventually got through to the series' creators.

Toph would go on to become one of the most popular character from The Last Airbender, and an icon for inclusion in animated television programs. Toph's original designs didn't go to waste, though, as they were said to be part of the inspiration for The Legend of Korra's Bolin, another Earthbender.

19 KORRA ALMOST ONLY LASTED ONE SEASON

One criticism that is long-present for fans of the Avatar universe is how disjointed The Legend of Korra seasons feel, with each really having its own plotline, rather than the whole series building to one goal, like in The Last Airbender. But the show was originally planned to be one season, which included the showdown with Amon in Book One. After the intense fan reaction for the show, it was extended to four seasons, which were really the length of two actual seasons.

With that, fans were treated to Books 2-4 of The Legend of Korra and got to know the incredibly powerful Korra, her ragtag group of bending friends, the inventive Asami and the legacy of Aang and co. with Tenzin, Bumi and Kya.

18 THERE AREN'T MANY "REAL" ANIMALS

One thing you'll notice if you've been paying attention in Avatar is that most of the animals shown on-screen are unique combinations of two animals or wholly new breeds altogether. Prominent species include the flying bison, "penguins," turtle seals and polar bear dogs. But throughout the entire series, there are really only a handful of "real" animals.

The most prominent of these "real" animals is a bear. Yes, just a bear, owned by the leader of the Earth Kingdom. Sure, there are wolves and fish, but there are also dragons, so you can imagine the surprise people have when they meet just a bear or see just a hermit crab. It's quite surprising.

17 AANG HAD A DIFFERENT VOICE ACTOR IN THE PILOT

Avatar-The-Last-Airbender-Aang

The voice actor for Aang may be iconic now, but Nickelodeon originally had a different actor in the role of the lone Airbender. Before Zach Tyler Eisen landed the part of Aang, Mitchel Musso was on deck to play the series' main character. In fact, there's a version of the pilot episode of Avatar: The Last Airbender with the Disney Channel actor playing the lead part, though it sounds a bit weird to hear now, years after Eisen cemented his performance as Aang.

Musso would go on to play Oliver on the popular Disney Channel show Hannah Montana, so it seemed to all work out in the end. But things might have been different if Aang had been played by someone else from the start.

16 EVERY SEASON OF AIRBENDER STARTS ON A BOAT

fire nation ship in avatar

Much like how almost every Star Wars film opens with a shot up a sweet looking spaceship, Avatar: The Last Airbender holds its pop cultural influences close, beginning each season, or Book, with a scene on a boat. The first season has Katara and Zuko out at sea near their tribe, Book Two has the Avatar and friends on their way to the Earth Kingdom and Book Three opens with Aang on-board a capture Fire Nation ship.

It might seem like a small detail, but it's a through line to show that Aang and co. are always on the move, despite the relatively short timeframe the show takes place over.

15 THE CHARACTERS IN THE OPENING ARE ALL SHOWCASED LATER

To the confusion of many and to the debate of some, the four characters that appear to harness each of the Avatar universe's four elements in the show's opening credits are actually showcased at different moments throughout the series. The Waterbender is Pakku, the master who at first refuses to teach Katara, but ends up teaching both Katara and Aang -- because he was in love with Gran Gran.

The Earthbender is theorized to be the original design for Toph, but he bears a strong resemblance to "The Boulder" and numerous other Earthbenders from the series. The Firebender is the fierce and unrelenting Azula, the villainous heir apparent to the Fire Nation throne. Finally, the Airbender is either Aang or Gyatso, Aang's air nomad teacher and good friend.

14 "MY CABBAGES" GUY WAS NOT PLANNED

The Avatar series has plenty of running gags, some going all the way back to the very first episode of Avatar: The Last Airbender. But one sticks the landing plenty more than others, one that transcended generations of the Avatar and showed up in The Legend of Korra. Of course, we're talking about the one and only, the legendary, "My Cabbages" guy.

There was never an original plan to have this line of dialogue be a running gag, but fan reaction and embracing of the character and his mishaps made the writers hunker down and sprinkle the cabbage destruction throughout both Avatar series. Though, we learn in Korra that he did pretty well for himself and built a whole cabbage corporation.

13 EVERY ELEMENT/BENDING HAS SUB-LEVELS

There are plenty of showcases for the four main elements in Avatar: The Last Airbender and The Legend of Korra, but fans may forget that each element has what's basically a subclass, and sometimes more than one. Waterbending is cool, but how about bloodbending or swampbending? You've heard of airbending, but what about being able to suck the oxygen out of the air? Or even spritbend some baddies powers away?

Then there's Earthbending, which could be anything from mudbending to metalbending, the latter of which is created by Toph Beifong and used to great effect by her family in The Legend of Korra. Even Firebending has its own sub-abilities, like lightningbending, which is arguably one of the coolest things ever.

12 JAMES CAMERON'S AVATAR CAUSED A KORRA NAME CHANGE

dark-horse-avatar

OK, so it wasn't the only reason why The Legend of Korra doesn't include the Avatar moniker from The Last Airbender, but James Cameron's hyper-popular Avatar caused some concerns with The Legend of Korra series creators. Sure, The Last Airbender publicly came about a bit before Avatar (even if it was planned prior), but the confusion seems to have pushed them away from the previous naming convention. After all, you'll still get people who ask "the one with the blue people?"

But Korra's name change allowed the series to stand on its own merits. Funnily enough, Avatar: The Last Airbender was titled The Legend of Aang in some international releases because 'bender' is considered slang with a negative connotation in some parts of the world.

11 ZELDA WILLIAMS VOICES A CHARACTER IN KORRA

Kuvira

Zelda Williams is well-known to be a huge fan of nerd culture, and it dates all the way back to her father, the late actor Robin Williams, naming her after the Nintendo Entertainment System game, The Legend of Zelda. So it was only fitting that Zelda Williams would go on to play a character in The Legend of Korra. She voiced Kuvira, the metalbender turned big time villain and basically took over the Earth Kingdom.

She became so obsessed with conquering the world that she even tried to end the Avatar numerous times. Of course, we all know how that turned out. Zelda Williams joined a phenomenal cast that also included the likes of Aubrey Plaza, J.K. Simmons and Steven Yeun, of Parks & Recreation, Spider-Man and The Walking Dead, respectively.

10 UNCLE IROH WAS RE-CAST

After production of the second season of Avatar: The Last Airbender wrapped up, tragedy struck the cast of the show with news that the voice actor for Uncle Iroh, Mako Iwamatsu, had passed away due to complications from cancer. Mako was replaced in season three of The Last Airbender by Greg Baldwin, when Uncle Iroh's plans come full circle as its revealed he's been assisting the Avatar through the order of the White Lotus the entire time.

The voice may not have been as iconic or passionate as Mako's, but Baldwin helped carry to the finish line what Mako had started with the character of Iroh. He remains one, if not the most well-loved character in the Avatar universe.

9 KORRA IS THE YOUNGEST TO MASTER THREE ELEMENTS

Avatar-The-Last-Airbender-Aang

In the very first episode of The Legend of Korra, fans are introduced to the fierce, young Korra, who at the age of a toddler mastered three of the four elements in the world. Sure, this made it obvious that Korra was the Avatar, but it's still quite something to see a five-year-old wielding water, fire and earth all at once. Oddly enough, the only element she had yet to master was air, which sort of kicks off the events of the series.

Aang, however, holds the title of the youngest Avatar to ever master all four elements, beginning his journey at the age of 12 and taking on the Fire Lord within two years, utilizing all four elements and his past lives to stop the tyranny of Ozai.

8 ONLY ONE EPISODE HAS A DIFFERENT CREDITS SCENE

There's something rhythmic and blissful about the credits to Avatar: The Last Airbender, so when the series' final episode carried a different title tune, fans truly knew that something was going down. Or better yet, it may have been totally missed in the action and tension of those final few episodes, when Aang was going toe-to-toe with Fire Lord Ozai while his friends attempted to liberate the rest of the world.

The music for the finale was deemed to be "more heroic," which made a lot of sense after Aang succeeds in his mission. Thankfully, Avatar: The Last Airbender's composer is on-deck for the upcoming live-action Netflix series.

7 TENZIN IS NAMED AFTER AANG'S TEACHER

While never explicitly stated, Aang's Airbending teacher in Avatar: The Last Airbender is based on the real life past Dalai Lama, Tenzin Gyatso. And while Monk Gyatso is referenced numerous times in the first Avatar series, his first name is never really part of this. So, you might be surprised to learn that Gyatso's legacy extends into The Legend of Korra as well, when we meet Aang's son, Tenzin.

It makes sense that Aang would name Tenzin after someone important to his journey as the Avatar, and there's certainly precedent. Aang other son, Bumi, is named after the Earth Kingdom leader of the same name, as well as Kya, Aang and Katara's daughter, who is named for her mother.

6 GENERAL IROH HAS THE SAME VOICE ACTOR AS ZUKO

general-iroh

To the surprise of many, a familiar voice appeared as The Legend of Korra continued into its subsequent seasons. And sure, plenty of characters made an appearance, the most surprising may have been the voice actor of Zuko from Avatar: The Last Airbender, Dante Basco, teaming up with the Avatar crew again to voice General Iroh.

In one sense, it's a fun easter egg for fans of the original show. In another, it's the direct effect of Zuko's choices in the original series, and General Iroh's position with what is essentially a united army, is clearly the result of how Aang and Zuko changed the world.

5 THERE IS ONLY ONE LAST NAME IN AIRBENDER

Avatar Toph

Something that may fly completely overhead of fans on a watch of Avatar: The Last Airbender is that none of the characters have both a first and last name. Well, none of them main characters except for one. That honor goes to Toph Beifong, who is considered royalty in the Earth Kingdom during the events of The Last Airbender. 

Most characters in this world are identified by the region they hail from, whether its an Air Temple, a Water Tribe or the Fire Nation. Katara, Zuko, Aang, Sokka and plenty others are only identified by their first names and place of origin.

4 KATARA ALMOST HAD HER MOTHER'S NAME

Avatar-The-Last-Airbender-Katara

In the same pilot episode for Avatar: The Last Airbender where Mitchell Musso voiced Aang instead of Zach Tyler Eisen, Katara had a different name. Her name was originally Kya, which would become an extremely important name to the world of Avatar shortly after. The series creators eventually made Kya the name of Katara's and Sokka's mother, which was a nice callback to the original plans.

Kya would also reappear in The Legend of Korra as the name of Aang's and Katara's daughter, again a welcome callback to the original series plans and the now-established canon of Katara's and Sokka's mother.

3 MAKO WAS NAMED AFTER UNCLE IROH'S VOICE ACTOR

If you've been keeping up, it's fairly obvious that names are extremely important to the world of Avatar. In this case, the name of the Firebending Mako from The Legend of Korra comes from the original voice actor who played Uncle Iroh in Avatar: The Last Airbender.

In between production on seasons two and three of The Last Airbender, Iroh's voice actor Mako Iwamatsu perished from complications from cancer, and was re-cast. To honor the actor and what he brought to Iroh, series creators named Mako after Iwamatsu, a welcome callback to the original series and the perfect way to honor the fan-favorite, loving Uncle Iroh.

2 KORRA HAS A TIE-IN TO THE LIVE-ACTION MOVIE

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For fans of Avatar: The Last Airbender, it's basically treason to discuss the 2010 live-action The Last Airbender, from director M. Night Shyamalan. And while the film itself may not have exactly set the world on fire, it did have an impact on casting for The Legend of Korra, the sequel series to Avatar: The Last Airbender. 

The actor who played Princess Yue in The Last Airbender, Seychelle Gabriel, would go on to voice Asami Soto in The Legend of Korra. Both are incredibly strong female characters in their respective series, so we can at least say there was something positive to come out of The Last Airbender.

1 UNCLE IROH HELPED AANG FROM THE BEGINNING

Avatar-The-Last-Airbender-Iroh

The biggest twist of all to come in Avatar: The Last Airbender may have been the reveal that Uncle Iroh was quietly pulling the strings on a number of events throughout the series. Sure, we know that he tried to steer Zuko toward the light, and that he had the care for spirits and refugees in the world, but Iroh's role in the Order of the White Lotus goes beyond that.

Early in the series, when Aang meets with previous Avatar Roku, the spirit of Roku's dragon takes Aang to the place where his journey must go. Iroh sees this, and he withholds the information from Zuko, completely altering a potential course of events for the series. Iroh has always been the real MVP.