With Adventure Time, creator Pendleton Ward is writing about the future. The thing is, his vision of the future doesn't exactly fall in line with more traditional concepts you've come across. His idea of tomorrow doesn't have the T-1000 or a Firefly-class transport ship — his has the Earl of Lemongrab and the Ancient Psychic Tandem War Elephant. His post-apocalyptic Land of Ooo is a no-holds-barred depiction of confectionary insanity, and it's because of this that the series has been able to introduce characters that by no means adhere to any rule of reality in any way whatsoever.
Some characters just show up, confuse/frighten unsuspecting viewers, and then go on their merry way. That's the beauty of living in the Land of Ooo: you don't have to make sense, and you don't have to hang around to explain why. Adventure Time is hardly ever running short on its supply of guest characters, but when it comes down to ranking them, splitting opinions is inevitable. So, to play fair, it's probably best to just take the subjective route and go ahead feasting your eyes on Adventure Time's 15 Best Guest Characters.
15. Banana Man
In the Land of Ooo, you don't need to go far to find entertainment. Simply walk out the door, and your environment will take care of everything. Still, there's always potential for something more, and Banana Man is a guest character in Adventure Time who couldn't agree more. While everyone else is busy keeping their feet on the ground, he's attempting to push further, to leave the world behind and explore outer space.
Naturally, things don't always go as planned in this show, but that's okay. With Weird Al Yankovich at the vocal helm, all is well. This isn't a character, like so many others, that is ively drifting through Ooo mostly satisfied with their digs — Banana Man's got his focus hooked on the stars. He's got ambition, and though that doesn't stop it from being a slightly warped ambition, it's kind of oddly encouraging.
14. Evil Guy
Alliances can be complicated in Adventure Time, but that isn't always the case. Sometimes in the show, there's zero gray space between good and evil, and alliances are as obvious as Finn's affinity for swords. Take Evil Guy, for example. When you're introducing a new villain — even a one-off villain that'll literally go up in smoke by the end of the episode — there's no harm in getting right to the point, and with Evil Guy, audiences get exactly that.
He's evil, he's a guy, and he's voiced by none other than Mark Hamill. So, right off the bat, there's a lot to love, even if he's more one-and-done than other guest characters. The fact that his destruction happens by way of a kick to his evil testicles makes him that much more beloved as one of the show's top guest villains.
13. James Baxter The Horse
Sometimes, animated shows get serious. On the outside, they're bright and whimsical, but underneath, they're festering with the same emotional grime that every human watching the series can relate to (even if they don't necessarily expect it in said series). Adventure Time is definitely one of those shows that's happy to broach the darkness more often than not.
Just take James Baxter the Horse, for example. He's the epitome of happiness, but at the same time, he's a perfect representation of mental health and depression. He's got an encouraging soul, positive vibes, and a super cool beach ball. Still, that sort of positivity can only hold up for so long. Eventually, with the wrong kind of atmosphere, all of that peace and love runs the risk of suffocation, and then: cue the fall. Then again, aside from all that, James Baxter is just a happy-go-lucky horse whose best mate is himself and whose greatest tool is a ball.
12. The Duchess Of Nuts
The Duchess of Nuts is nuts. That's about the best way to sum her up. Voiced by Maria Bamford, she's literally a pile of nuts in a dress, more or less, and she's married to the Duke of Nuts (naturally). Every now and then, Finn and Jake happen across some bold-faced ridiculousness, and the Duchess of Nuts is just another example to add to the pile.
There's not much else to her, aside from the fact that most, if not all, of her information comes from nuts, which speak to her. But she's worth a mention here for A) her simplicity (she's a nut who is nuts — brilliant), B) the fact that she's voiced by Maria Bamford, and C) the line, "Would you like to hear what my nuts have to say?" It doesn't make an awful lot of sense, but isn't that what's so captivating about Adventure Time in the first place?
11. Ancient Psychic Tandem War Elephant
When you have the power of animation at your fingertips, the sky's the limit. If you can draw it, you can make it. Which would explain the existence of Ancient Psychic Tandem War Elephant. Getting him into the show requires the act of summoning (not by the creators, but the characters), and Finn and Jake do so on a couple of occasions. This elephant is sort of like Adventure Time's take on the deus ex machina; it shows up to save the day, and it's by no means something anyone might ever expect.
Whether or not you really bonded with this particular character, it doesn't feel right including a list of favorites without including a two-headed psychic elephant. Such a collection just wouldn't feel complete. So, here's to you, Ancient Psychic Tandem War Elephant. May you always be ancient, psychic, and tandem.
10. Hunson Abadeer
Oh, to be deathless. Hunson Abadeer is as evil as evil gets, even though he managed to father everybody's favorite axe-picking vampire, Marceline. He's a fun-sucking (and blood-sucking) demon who is as terrible to people as he is at being a dad, but there's a lot to like about the guy.
For one, you've got to give the guy props for his commitment. The kind of business he's involved in is literally pure evil, but at least he follows through on his depravity. Also, it's not difficult rooting for the bad guy (even if you secretly still root for the hero to show up at the last second to save the day). Villains are usually fun, in their own weird and twisted ways. Why else would we be so fascinated in characters like the Joker and Dracula? They're may not be kind, but they're cool.
9. Ricardio The Heart Guy
Ricardio is literally a walking heart that ironically has no heart. In fact, he specifically belongs in the empty chest cavity belonging to the Ice King, but he jumped ship and became an evil bachelor instead. He's charming, but only because he's voiced by George Takei, and he's evil, but only because he wants to cut out the princess's heart. Still though, he's a romantic, so can you really blame him? (Don't answer that.)
He's not exactly likable, but as a guest character on the show, he does a more than serviceable job. His plot revolves around love, abduction, sociopathy, psychopathy, and overly-detailed facial expressions. If the Adventure Time animators were trying to convey "stranger danger" in its purest form, they've succeeded. And as far as villains go, he's certainly made an impression on audiences.
8. Fionna
Fionna is Finn, but at the same time, Fionna is not Finn. Basically, she's Finn if Finn were female. Kind of. When the Ice King writes his own fanfiction, he creates gender-swapped versions of characters from the show itself. So, from Finn we get Fionna. Simple enough. Still, even though she seems like a one-off character, Fionna managed to make quite a significant mark on Adventure Time and, along with her other gender-swapped counterparts, she's become something of a fan-favorite.
This alternate reality may just seem like straight-on fan service, but it's really not. There's something sort of refreshing seeing these alt. characters in action, introducing this new dimension, so to speak, in the show. And although this alternate reality itself may just seem like fan service, it's really not. The animators definitely do well by it. Also, it doesn't hurt having the talents of Madeleine Martin on vocals.
7. Billy
Adventure Time is all about the heroes. In fact, that's what propels Finn and Jake to do the things they do. They travel around Ooo, doing their best to fight evil, and they happen upon adventures while putting their heroics to work. Another hero, Billy, has got one hell of a reputation, but he's been MIA for quite some time; his reason being age, mostly. Over time, he just lost his will to fight. However, with Finn exclaiming how badly he wants to "kick evil's butt," Billy's dormant heroism eventually comes to, and all is well.
Well, actually, all is not well, and Billy ends up dying at the hands of the Lich, even having his corpse desecrated after the fact. All in all, his story arc is unexpectedly broad and tragic. For those reasons, he's earned himself a spot on this list.
6. The Lich
This zombie king is quite the savage skeleton. As classic a villain as villains come (he's pure evil spreading pure evil), the Lich is one of the creepier characters to show up on Adventure Time. This horned death-bringer is all the more captivating for the fact that he's voiced by the singular Ron Perlman. If you're looking for menace and fear, Perlman's got you covered.
The Lich is the Land of Ooo's personal rotten core, and he does sincere justice to villains everywhere. His intentions are simple enough (destroy), and it's his simplicity that makes him such a formidable foe for Finn. They exist on polar opposites of each other's spectrum, giving them the most classic grounds to fight. When it comes to heroes and villains, opposites attract.