Avatar: The Last Airbender centers around the young Avatar Aang, after he's released from a hundred-year hibernation deep within an iceberg. He sets off across the continents to learn and master all four elements, alongside his traveling companions, Sokka, Katara, and Toph. He must do so before his ultimate showdown against Firelord Ozai.
Ozai is built up to feel like such an insurmountable threat throughout the course of the series, that it's hard for other villains to compare. That doesn't mean that there aren't many villains within Avatar that manage to come close, though. There are minor threats sprinkled in before the final showdown, and some are more successful at accomplishing what they set out to do than others.
9 Mai Is Far Too Apathetic To Take Azula's Orders Seriously
Mai doesn't start out as a villain, but rather an apathetic, bored girl who would do anything to escape the city she lives in. When Azula comes along and offers to take Mai with her, she immediately jumps at the chance, and doesn't look back.
The problem with Mai as a villain is that she's essentially one of Azula's henchmen, and her nonchalance prevents her from properly following through with plans. She's far more passionate and successful when she's fighting against Azula in the name of good, for herself and for her relationship with Zuko.
8 Zuko Has Far More Success As A Hero Than As A Villain
Zuko doesn't remain a villain for the entire series, and fans are incredibly happy that things turn out this way. Most of Zuko's acts as a villain are successful, but he doesn't have much luck when it comes to capturing the Avatar.
He greatly damages his relationship with his uncle when he turns against him in favor of listening to Azula. Thankfully, the two are able to reconcile, and he becomes an invaluable Firebending teacher to Aang.
7 Ty Lee's Chi Blocking Abilities Make Her A Surprisingly Lethal Threat
Ty Lee is, by far, the cheeriest and most upbeat villain in Avatar. She only goes along with Azula after the latter essentially destroys the circus she's traveling with, and she just wants to feel a sense of individuality more than anything else.
Her chi-blocking abilities make her a surprisingly lethal threat, compared to her incredibly cute appearance. She's successfully able to use these skills to disarm her opponents, though the most memorable is when she finally turns against Azula.
6 Combustion Man Almost Takes Aang's Life Several Times
Combustion Man is, perhaps, the strangest out of all the classic Avatar villains. Combustion-bending is a sub-class of Firebending, wherein the user is able to channel chi through their forehead to create destructive, explosive blasts.
Hired by Zuko to take out Aang, Combustion Man is almost successful on numerous occasions. The Gaang is only able to beat him after Zuko changes sides and agrees to help them, acting as a distraction to give them time to enact their plan. They aren't directly responsible for his death, but rather, he causes a point-blank explosion after his chi is blocked.
5 Long Feng Reigns As The Earth Kingdom's Most Powerful Leader
Although Long Feng's official title is Grand Secretariat, in actuality, he serves as the de facto dictator of the Earth Kingdom. He's an influential and manipulative man who craves power above all else, and will stop at nothing to get it.
He's responsible for ensuring that war talk is kept out of the Earth Kingdom. If it wasn't for Azula double-crossing him and taking over Ba Sing Se for the Fire Nation, who knows how long he would have kept up his corrupt rule.
4 Zhao Is Almost Responsible For Wiping Out Waterbending
Admiral Zhao didn't succeed in his attempts to capture the Avatar, but he's almost successful in another grim endeavor. He's able to kill Tui, the Moon Spirit responsible for creating Waterbending. As a result, all Waterbenders lose their powers – albeit briefly.
This is where Yui comes in, as she holds some of the Moon Spirit's life energy inside her, and is able to sacrifice herself to restore both Waterbending and Tui's life. If it weren't for this sacrifice, Zhao would have successfully eliminated one out of the four elements.
3 Every Full Moon, Hama Unleashes Bloodbending On Innocent Fire Nation Civilians
Hama is a tragic example of what happens to someone after they've endured abuse and hardship. While imprisoned by the Fire Nation, she develops Bloodbending, a deadly sub-class of Waterbending.
Every full moon, Hama would imprison villagers from the Fire Nation town she fled to, before enacting her revenge on them via Bloodbending. The problem is that she doesn't care if she's enacting revenge on innocent civilians who had nothing to do with her imprisonment.
2 Azula Is Brought Down By Her Own Mental Instability
Azula is one of the most terrifying figures in Avatar. She's intelligent, cruel, manipulative, and knows exactly how to strike fear into the hearts of others to make them obey her every command.
However, after she's betrayed by Mai and Ty Lee, and later defeated by Zuko and Katara, her instabilities rise to the surface and become too much for her to ignore. After Zuko takes over as the Fire Lord, he takes pity on her and sends her to a mental facility rather than prison for her crimes.
1 Firelord Ozai Is An Impending Threat Throughout The Series
Firelord Ozai's ultimate goal is to control the world. As a powerful and feared villain, this ambition isn't much of a stretch. His plan is to use Sozin's Comet to destroy the Earth Kingdom, before becoming the Phoenix King – ruler of the world.
He has no problems exiling or even executing those that disagree with his rule, and he almost kills Zuko before being offered the throne instead. Aang has to use all four elements, in combination with the Avatar State, in order to subdue Ozai and take away his bending once-and-for-all.