Adventure Timewas one ofCartoon Network’s most successful shows. Audiences fell in love with the wacky adventures of Finn the human (Jeremy Shada) and Jake the Dog (John DiMaggio) as they explore the land of Ooo. They watched these two grow fromteenagers playing heroes to mature defenders of the world.
But a hero is only as good as the villains he faces. Fortunately, there are no shortage of wicked fiends and tormented individuals for Finn and Jake to battle against, or potentially turn into a friend.

10Flame King
The admitted evil ruler of the Flame Kingdom, Flame King (Keith David) killed his own brother to win the throne. Then, when he learned his daughter (Jessica DiCicco) was more powerful than him, he tried to have her killed before imprisoning her in a lamp. He also decreed that every citizen of the Fire Kingdom should be as evil as him.
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In a show that is full of bad fathers, Flame King might just take the crown for worst of all. Though he did let Flame Princess out in her teen years, it was only because he believed she would end up with an evil husband, and continued to try and influence her towards villainy. When she eventually overthrew him, he was able to briefly regain power by promising to marry her to one of his allies.
9The Hierophant
When Marceline (Olivia Olsen) has her vampire essence removed by Princess Bubblegum (Hynden Walch), she accidentally revives five powerful vampires she killed. One of them, the Hierophant (Paul Williams), follows the traditional code of vampires. Unsatisfied with the progressive views of the Vampire King (Billy Browns), the Hierophant sets off to carve his own path of destruction across Ooo.
The Hierophant had a lot to make him stand out. His powers over shapeshifting allowed him to transform into creative animal designs, and his old school mindset allowed for some fun commentary on vampires in general. Finally, Williams' performance is just as sophisticated and classy as his portrayal of the Penguin inBatman: The Animated Series.

While trying to win Bubblegum’s heart, the Ice King (Tom Kenny) accidentally brought his to life. Now called Ricardio (George Takai), he forced Ice King to fly him to the candy kingdom before tossing him in the dumpster. He then began to sweet talk and charm Bubblegum, so he could cut out her heart and make out with it.
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Ricardio stands out as one of the show’s best side villains. He has a simple but effectively creepy design, and his plan is one of the more gruesome in the series. His later appearances involve him trying to build himself a body to marry Bubblegum, “as a man”, which leads to some creative uses of child-friendly body horror.
The first MO robot built by Mo (Chuck McCann), AMO (Thu Tran) was built to receive love. Unfortunately, he couldn’t think outside his programming, and his need for love caused him to reject it. He eventually decides to get rid of all the other MOs and replace BMO (Niki Yang) as Finn and Jake’s robot so that they will love him.

AMO’s style of villain feels very real in today’s world. He selfishly demands love from others without doing any of the work to earn it, then manipulates and chastises them when they don’t meet his expectations. If he thinks his chosen providers love someone else more than him, AMO won’t hesitate to take them out.
6Earl of Lemongrab
Originally created to be Bubblegum’s heir, the Earl of Lemongrab (Justin Roiland) proved unsuited to the task due to his sour disposition. Bubblegum placed him in a castle but didn’t give him any citizens. This caused him to develop abandonment issues and self-loathing that eventually took Lemongrab down the path of tyranny.
As a villain, Lemongrab offered a good mix of comedy and tragedy. His bizarre mannerism and Roiland’s performance provide plenty of laughs, while his constant struggle to live with himself slowly turns him into a brutal dictator obsessed with control. Fortunately, he is given a chance at redemption and mellows out in season six’s “The Mountain.”
To give herself and her brother, Neddy (Andres Salaff), a new family, Bubblegum created Cousin Chicle (Tom Kenny),Aunt Lolly (Maria Bamford), and Uncle Gumbald (Fred Melamed). Unfortunately, Gumbald wanted more from life and made plans for his own candy city. He was defeated when exposed to his own dumb-dumb juice but later returned to take revenge on his niece/creator.
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Gumbald has all of Bubblegum’s ambition and knowledge with none of her restraint or altruism. His actions are not driven by a desire to protect his loved ones but rather by a narcissistic drive to be in control. This allows him to produce devastating machines for war and violent candy creatures that can outmatch Bubblegum’s more friendly ones.
The byproduct of Finn’s cursed grass sword merging with a sword created from an alternate timeline version of himself, Fern (Hayden Ezzy) possesses all of Finn’s memories and thinks of himself as Finn. Of course, nobody else does, which leaves Fern lost and confused about his identity. Over time, he decides that the only course of action is to get rid of Finn so that he can be the only Finn.
Fern’s story is one of the more tragic inAdventure Time.He could have loved a good life with Finn and Jake, but his inability to find his own path turned him to the path of envy. He serves as a dark mirror of what Finn could have turned into if he had let his trauma define him rather than healthily adapted to and accepted it.
3Magic Man
Originally from Mars, Magic Man (Tom Kenny) was banished to Ooo for using his magic to torment people. This did little to change his ways and instead prompted Magic Man to use his powers to torture and mutate as many innocents as possible. After encountering Finn and Jake, they become his favored targets.
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Magic Man is one of the best examples of an agent of chaos in cartoons. He does what he does solely to be a jerk and teach nihilistic messages to his victims. Yet when his powers are taken from him in an experiment with Betty Groff (Lena Dunham and Felicia Day), he sees the error of his ways and strives to make amends.
2Hunson Abadeer
As the ruler of the Nightosphere, a plane sustained by chaos, Hunson Abadeer (Martin Olson) is a powerful and deathless demon.He is also Marceline’s father, and the two have a strained relationship. It’s made even worse because, whenever he is summoned to Ooo, the first thing he does is attempt to steal everyone’s soul.
Abadeer is a being of pure evil who revels in tormenting and torturing others before stealing their souls. He shows some compassion towards Marceline and tries to bond with her, but his inability to understand emotions, plus his desire to see her succeed him, drives a wedge in their relationship. His powers are also some of the greatest in the entire series, ranging from shapeshifting to reality warping.
Since before time began, the Lich (Ron Pearlman) has worked tirelessly to bring about the end of all life. With a seemingly endless knowledge of the dark arts at his disposal, he is a threat that only the greatest of heroes can hope to overcome. Even death does not stop him, as he has found a way to exist across all realities.
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The Lich is one of the mostterrifying villains in all animation.Though he has been defeated multiple times, the inevitability of him is parallel to the reality of death and destruction. you’re able to hold it back only for so long before the end catches up, and the Lich knows this: he just needs to be patient.
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