Avatar: The Last Airbender follows a universe where nations made of people with connections to powers involving earth, water, fire, and air begin to fight a war against each other. Benders (or those with the skill to "bend," or use water, fire, air, or earthly elements to defend or attack themselves) and their nations lead the show's story.

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The Avatar is the only person in the universe who can master all four elements at the same time. Aang, though only biologically twelve years old, takes on the responsibility of his destiny as the Avatar, and along with his friends, works to fight off the influences of war across nations -- but even for the most hardcore Avatar fans, it's easy to lose track of a few hidden secrets throughout the series. Here are 10 hidden details about the main characters you might have missed.

The Scar on Aang's Foot

Avatar Aang is the protagonist of the series, destined to use his ability to harness the power of earth, fire, wind, and air to save the world from war. Aang's free spirit and big heart make it difficult for him to accept that he has to live up to such a huge responsibility, but over the course of three seasons, we see Aang go from the mind of a twelve-year-old boy to a great fighter and leader.

In a fight between Fire Princess Azula in the episode titled "The Western Air Temple," Aang gets hit with a fire blast that leaves a scar on his foot. In all the episodes that follow after this event, any time Aang lifts up his foot, you'll be able to see the scar.

Katara's Motherly Instincts

Katara controlling water

Born in the Southern Water Tribe, Katara was granted the ability to bend water. The Southern Water Tribe had lived for years as a peaceful society, until the Fire Nation raided their town and murdered Katara's mother. Katara's father then went off to fight the war, leaving Katara alone at home with her older brother Sokka. Katara used her ability to bend water very practically, by heating it up to cook food or to build ice castles for younger children to play with.

Katara's motherly instinct is something that stays present within the series, as she's very protective and loving of Aang's safety. This personality trait comes from the loss of her own mother and manifests as a strength as she uses her powers to fight to protect the people she loves most.

Sokka's True Leadership Skills

Sokka looking skeptic

In original plans for the series, Avatar writers and creators didn't intend to make Sokka such a prominent character on the show, but after comedian voice actor Jack DeSena brought his shining sense of humor and spirit to the character, Sokka became one of the show's most loved characters.

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Many people view Sokka as the comic relief on a show about fighting a war and saving the world, but what viewers may not realize is that some of Sokka's best qualities come from him being a natural leader. After his father left the Water Tribe to fight the war, Sokka became the oldest male leader in the South Pole. This led him to begin taking his duty as a male leader seriously, and his willingness to protect and defend proves to be the saving factor of many battles throughout the show.

How Toph Gets Sleep At Night

Toph with a grim expresion

Toph Beifong is an earthbending master, and though she is young, she is considered one of the most powerful of her generation. Toph was born blind, and though she cannot see, her ability to sense motion and feel vibrations through the Earth is exactly what makes her so talented.

As Toph joins Aang's gang on their trip across the world to defeat the Fire Nation, many times you might see her sleeping on the ground with her feet elevated. She can feel every movement that happens on the ground beneath her. Sleeping with her feet up just might help her get the rest she really needs. Many fans of the show have credited Toph with being an inspiration, as she remains such a powerful fighter despite her inability to see.

The Meaning of Zuko's Name

Zuko was born into the Fire Nation Royal Family as a prince with the ability to bend fire. Throughout his childhood, he'd been outshined by his younger sister Azula, causing his father to look down on him. Zuko harnesses this anger and uses it to track down Aang and defeat the Avatar in order to gain back his father's approval.

What fans of the show may not about Zuko is the origins of his name. While we don't know for sure, the name can still be traced back to Chinese origins where "zuko" means "failure," but also, "loved one," which is fitting for Zuko's character arc in the series, as we see him go from seeking revenge to helping fight for the right reasons.

Azula, In Every Episode

Azula from Avatar The Last Airbender

Despite being a princess of the Fire Nation Royal Family and Zuko's younger sister, Azula proves throughout the show that she needs nobody's help when it comes to fighting or fire bending. Though her character doesn't debut in a speaking role until the end of the first season, Azula is one of the first characters that viewers see.

In Avatar's opening sequence, narrated by Katara, we get a brief history of the Avatar's destiny, the war, and how she found Aang. Azula can be seen when Katara speaks the word fire. Azula bends down before blasting fire from her hands, proudly representing her nation.

Appa, the Bison/Manatee

Aang offering Appa a treat in a flashback in Avatar: The Last Airbender

When the Fire Nation wiped out the entire airbender population a hundred years ago, all that remained were Aang, his winged-lemur, Momo, and his sky-bison, Appa. Appa and Aang share a deep connection with each other, as it's said that sky-bison were among the first creatures who could bend air.

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Appa uses his tail to create gusts of winds to fly, serving as the gang's mode of transportation as they travel across the world. A hidden secret about him, though, is that Avatar creators have revealed that Appa's appearance was inspired by drawings of a creature that was a cross between a bison and a manatee.

Momo as Monk Gyatso's Spirit

Another cross between two animals is Momo, the show's only winged-lemur and Aang's beloved pet. He's a cross between a bat and lemur, since he can also fly. When Aang emerges from the ice a hundred years later, he revisits his home, only to discover that everyone he once knew is now gone. The only living creature he came across was Momo.

Momo serves as a huge comic relief in the show and finds himself in the path of many dangerous situations. He's aided Aang and his friends many times on their journey, and while he might seem like nothing but a pet, the creators have said that he is representative of the spirit of Monk Gyatso.

Mako Iwamatsu as Uncle Iroh

Iroh holding a torch in a dark space in ATLA

Voice actor Mako Iwamatsu voiced the character of Iroh in the show. Iroh was known as "The Dragon of the West" as he was an incredibly wise and skilled fire master who could breathe fire. Iwamatsu worked closely with the show's creators to help create Iroh's character from writing his story to help drawing his illustrations.

Iwamatsu passed away in 2006, and his understudy Greg Baldwin voiced Iroh for the remainder of the show in replication of Iwamatsu's own voice, in honor of him. In The Legend of Korra, Iwamatsu would be remembered forever as the show's creators named one of the characters Mako in his respect.

Firelord Ozai's Family Failures

Ozai Phoenix King

The show may not touch upon Firelord Ozai's family history too much, but it's important to understand it in order to understand his desire to conquer the entire world and become supreme ruler.

Before he was ever born, Ozai's father and grandfather had both set out to find the Avatar, capture them, and prevent them from mastering all the elements so that the Fire Nation could rule supreme. In his early years before ruling as Fire Lord, Ozai tried his own attempt at finding the Avatar but failed. This failure is a grief that he carries with him and manifests itself into his desire to defeat all other nations.

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