For kids who watched cartoons in the early 2000s, the heroes of the shows they watched were always the easy choice for favorite characters, while the villains were feared and hated. However, as fans grow older and take time to revisit some of their favorite cartoons, the hero of the show might no longer hold the same level of appeal.

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With age, fans can appreciate nuanced villains as well, no longer hating them for their simplistic, evil ways. The best villains are the ones that have left the biggest impact on fans throughout both their childhood and adulthood, the ones who usually have a bit of pizazz, or memorable traits.

10 The Trix Love To Antagonize Bloom And Her Fairy Friends (Winx Club)

The popular animated fantasy series Winx Club was released in 2004 and follows the story of a fairy named Bloom and the adventures she and her fairy friends have in Magix world. Bloom and her friends often get into fights and are constantly antagonized by the villain group Trix.

The Trix are three witches named Icy, Darcy, and Stormy and are decedents of the Ancestral Witches that destroyed Bloom's home planet. Together the three witches prove to be strong with their Gloomix which makes them more powerful.

9 Dr. Heinz Doofenshmirtz Comes Up With Evil Schemes Every Day (Phineas and Ferb)

The popular Disney Chanel series Phineas and Ferb was released in 2007 and focuses on the adventures Phineas and Ferb have during their summer. Although this show isn't about superheroes it does feature a villain that is one of the most popular in cartoon history.

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Dr. Heinz Doofenshmirtz is an evil scientist who is the archenemy of Perry the Platypus who is a secret agent but also Phineas and Ferbs pet. In every episode, Doofenshmirtz comes up with an evil scheme that is always foiled by Perry.

8 Albedo Harbors A Deep Hatred For Ben Tennyson (Ben 10: Alien Force)

Ben 10: Alien Force which was released in 2008 stars Ben Tennyson who is now 15 years old with 10 new aliens added to his Omnitrix, and with the help of Gwen and Kevin, on a mission to find their missing grandfather.

A famous recurring villain in this series is Albedo, a former assistant to Azmuth, who accidentally turned himself into an imperfect clone of Ben whilst he was trying to recreate the Omnitrix. Albedo since then has been trying to get to his Galvan form and harbors a deep hatred for ben and wishes to seek revenge against him.

7 Aku Is An Evil Shape-Shifting Demon Who Has Ruled Over The World For Eons (Samurai Jack)

A rather unpopular but extremely good Cartoon Network series is Samurai Jack which was released in 2001 and follows the story of a samurai on a mission to defeat an evil shape-shifting wizard that sent him thousand of years into the future.

The evil wizard that did this is none other than Aku a demon that was born from the darkness and has ruled over the world for eons. As a shape-shifting demon, Aku can transform into anything meaning that he can retreat easily by shifting when he is getting bested by the Samurai Jack.

6 The Joker Becomes Darker and Homicidal In This Batman Adaptation (The Batman)

The Batman animated tv series was released in 2004 and stars Bruce Wayne as Batman who protects Gothman City from the evil lurking within it alongside Batgirl and Robin. Like any other Batman adaptation, the villain that fans can't get enough of is the Joker.

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The Joker is Batman's most popular archenemy, the Joker himself believes that the two are linked and considers himself to be Batman's favorite fighting opponent. In this series, the Joker switched from his usual clown-like personality to a much darker homicidal attitude making him a very dangerous villain.

5 Delightful Children From Down The Lane believe In Adult Supremacy (Codename Kids Next Door)

The cartoon Codename Kids Next Door was released in 2002 and follows the story of a global organization of kids that fight against the dictatorship of adults. Throughout the series, the main villain that the children most often fight against is the Delightful Children From Down The Lane.

The DCFDTL is a group of kids that believe in the supremacy of adults over kids and answer to the main antagonist Father. Although they work for Father, the DCFCTL also acts independently and often sends other villains to do their work.

4 Ember McLain Is A Rebellious Rockstar Ghost Who Hates Authority (Danny Phantom)

The popular Nickelodeon cartoon Danny Phantom made its debut in 2004 and follows Danny Fenton a human-ghost hybrid who protects his town from frequent ghost attacks. In the series, a plethora of ghost villains make an appearance, but the one that made the biggest impact on fans was Ember McLain.

Ember is a rockstar ghost girl with a magical electrical guitar that feeds off of teenage worship and can mind control people with her music. As a rebellious teenage figure, there is nothing ember hates more than authority figures.

3 Shego Is a Villainess Criminal Mercenary That Works Under Other Villains (Kim Possible)

The iconic series Kim Possible was released in 2002 and stars Kim Possible and her friend Ron who struggle to balance crime-fighting and their normal high school lives. Avid fans of the show can all agree that the best villain in the show is Shego a villainess who works as a criminal mercenary.

Shego mainly works for the villain Dr. Darkken as his henchmen, her main duties include stealing things for him and protecting him from harm, mainly against the Team Possible. Even though Dr. Drakken is Shego's main contractor, she also works for other villains on occasion.

2 Blackfire Is The Evil Older Sister Of The Superhero Starfire (Teen Titans)

Teen Titans was released in 2003 and focuses on five teenage superheroes who protect their city from the many villains that try to destroy it. Whilst this series features a wide variety of villains the most memorable villain has to be Blackfire. Blackfire is the oldest sister of Starfire who is a member of the Teen Titans.

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Because of this Blackfire has tried multiple times to get rid of Starfire, once framing her for a crime that she did and on another occasion becoming the ruler of Tamaran to set up Starfire for an arranged marriage she didn't want.

1 As The Princess Of The Fire Nation Azula Is Nothing But Pure Evil (Avatar The Last Airbender)

Another popular Nickelodeon cartoon series was Avatar the Last Airbender which was released in 2005 and follows Aang a long-lost Avatar who must now learn all the elements to save the world. Throughout the series, Team Avatar has gone up against their fair share of villains but the most villainous of them all is Azula the princess of the Fire Nation.

Azula is the true definition of evil as she has proven herself dangerous on multiple occasions by overtaking the earth city of Ba Sing Se and even almost killing Aang with her lighting which left him coma for weeks.