Finn

Finn (or Pen, from the pilot episode, or full title: Finn the Human Boy) is the main protagonist of the series Adventure Time.

Background
As shown in "Memories of Boom Boom Mountain," Finn appears to have been abandoned during infancy, left alone in a woodland. He reveals that he made "boom boom" (in reference to bathroom jargon) on a large leaf, fell on it, and lay there until Joshua and Margaret (the mother and father of secondary protagonist Jake) rescued him from the wilderness to raise him along with Jake, who becomes like a brother to him. In "Henchman," when Finn is asked about his parents, he says Jake told him that he came from a cabbage in jest. In "Susan Strong", Finn states that he doesn't know anything about his parents or any other family members.

Status as the last human
Finn may be the last human in the Land of Ooo, or possibly his world. In the episode "Her Parents", Lady Rainicorn's mom says she thought humans were extinct. This lends new significance to his title Finn the human, as his humanity may be unique in Ooo. Up to the episode "Susan Strong", Finn believes he has never met another human. Up to that point, the characters that appear human are actually known to be mutants or other kinds of "humanoids." Finn becomes depressed and "soul-searchy" when he thinks about it.

Finn encounters Susan Strong whose identity as a human or mutant is left ambiguous, even though the others in the Hyoomen Tribe were revealed to be mutants. Note that Fiona may also be a human, but it's not clear whether the gender-swapped characters exist in the same universe or reality as the main series. Susan Strong might be the only human (in the tribe) because she has long blonde hair (like Finn and Fiona) under her hat.

Appearance and equipment
Finn is a 13 year old human. He has very thin, flimsy looking limbs, and wears a white hat with two "ears" sticking out on top, which he has proclaimed is "awesome". His hat covers his entire head, except for his face. He also wears a blue short-sleeved shirt, blue-jean shorts, a green backpack, rolled-down white socks, and a pair of black shoes. When he's in the Ice Kingdom, he occasionally wears a yellow sweater. He has several missing teeth because "he bites trees and rocks and stuff", according to Pendleton Ward, the creator of Adventure Time. Ward has also stated that Finn has blonde hair. In "To Cut a Woman's Hair," Finn removed his hat for the first time, and revealed long golden locks of hair. His hair had a glowing sheen and extended his body length, until he cut it off and gave it to the Tree Witch. He wears red footsy pajamas when he goes to sleep. He wears white briefs that made an appearance in "City of Thieves," when Penny stripped him at the end of the episode.

Finn favored weapon is a sword that he sometimes carries. Pendleton Ward has stated that his sword is made of gold.

Personality
Though at times violent and aggressive, Finn is a brave and righteous hero. He has a very strong sense of responsibility and gets upset when he is unable to help others. He is shown to be a fearless thrill-seeker and enjoys putting himself in the midst of danger simply because he enjoys a challenge. However, as illustrated in "Ocean of Fear," Finn has an unexplained phobia of the ocean, or thalassophobia, despite the fact that he can effortlessly come into contact with any other body of water. While he portrays himself as a rough and tough hero, Finn has a tender side capable of love and compassion, as shown by his boyhood crush on Princess Bubblegum and his brotherly relationship with Jake. His aspirations to be a great hero make Finn somewhat of a moral sheriff to the Land of Ooo, as he is willing to help and protect any innocent creature in his strange world. Finn gets a lot of conflicting emotions when it's unclear whether something is good or evil, exemplified by his dealings with Marceline in the episode "Henchman".

Abilities
Finn is proficient in several forms of combat, including hand-to-hand, magic, and sword fighting. He can jump very high and is exceptionally strong and agile for a boy of twelve. Finn has some origami skills, as shown in "Ricardio the Heart Guy" in which he makes Princess Bubblegum a paper crane. Finn has been seen enjoying singing and gained the ability to auto-tune his voice on command after eating a tiny computer. He is very good at playing a video game called Adventure Masters, which he and Jake play on Beemo from time to time. Finn is also somewhat gifted at constructing simple machines, such as the catapult in "The Witch's Garden." He can also spit very long distances, as demonstrated in "Evicted!" when he spits on Marceline and in "My Two Favorite People" when Finn spits on Tiffany's face. In "Dungeon," one of the trials that Jake says Finn would have breezed through is a spitting competition against a goblin-like creature. Finn writes and draws with his left hand, and handles his sword with his right hand, suggesting he may be ambidextrous, which means that he can use both his hands with equal ability.

Relationships
Being a hero, Finn has become quite popular in the Land of Ooo, starting many quick friendly relationships.

Jake
As both housemates and best friends, Finn and Jake have shared a deep bond for most of their lives. Having been raised together by Jake's parents, the duo have a relationship similar to that of siblings, with Jake acting as Finn's older brother. Though they have an unconditional love for each other, Finn can get frustrated with Jake because of his laziness and lack of motivation, shown especially in "The Witch's Garden." As a more laid-back character, Jake often tries to relax Finn's fiery personality in the face of a struggle, advising him not to worry in most situations. Though he sometimes leads Finn down the wrong path, Jake genuinely means well for his companion and is usually an encouraging and protecting figure in Finn's life. Finn and Jake are apparently very big influences for each other. In "Dungeon," Finn sings "I want to have your baby" in the Key Song. Later in the series, in "Rainy Day Daydream," Jake playfully says the same thing to one of the imaginary girls, regarding his relationship with Lady Rainicorn.

Lady Rainicorn
Finn became friends with Lady Rainicorn after Jake wanted to hang out with both of them at once in the episode "My Two Favorite People". At first Jake regretted introducing the two, but in the end he was glad it happened. Finn and Lady Rainicorn still share a close bond, despite the fact that Finn can't understand Lady Rainicorn's fluent Korean.

Princess Bubblegum
Finn, as young adolescents often do, has a rather obvious crush, which he denies, on Princess Bubblegum. He is known to interact with her more than any of the numerous other princesses of Ooo, and will jump at the chance to do anything for her. Whenever someone says "Finn," "Princess Bubblegum," and "crush" in the same sentence, he growls and blushes fiercely. Though the princess is seemingly oblivious to Finn's affection, she often calls on him for any royal need. In "The Real You" Princess Bubblegum kisses Finn, and he faints a moment after the kiss. Finn always eagerly hopes to win the princess over with his heroic deeds. Finn and Princess Bubblegum share a staunch sense of morality and often work together to bring justice and balance to the Land of Ooo.

Marceline
Though seen as an enemy in her debut, Finn quickly befriends Marceline the Vampire Queen, as he realizes that her seemingly evil ways are just forms of playful teasing. A rowdy and adventurous character, Marceline and Finn share the same vigor and thirst for danger. Marceline finds all kinds of ways to mess with Finn in his head, but are really just mind games of hers. Although Jake still doesn't like Marceline (because Jake is afraid of vampires), Finn still likes hanging out with her and being "awesome together." Marceline, unlike real vampires, does not get attracted to blood but instead the color red. The bites on her neck also suggest that she was once a human.

Quotes
See Finn/Quotes

Trivia

 * In the pilot/short, Finn was originally named Pen, a name he got from the show's director and producer, Pendleton Ward.
 * In the pilot, Finn is voiced by Zack Shada. However, in the series, he is voiced by Zack's younger brother, Jeremy Shada.
 * Finn is still technically the king of the goblins, even though he left Whisper Dan to take his place, the goblins still believe its him.
 * In the episode "Ocean of Fear", Finn is revealed to have Thalassophobia, which is a fear of oceans or seas. Finn has no problem swimming in the episodes "Business Time", "My Two Favorite People", and "The Witch's Garden" because he has a specific fear of the ocean, and not small bodies of water such as lakes, rivers, wells or puddles.
 * Finn is probably going through puberty, as in some episodes his voice cracks, mostly when he screams. A good example of this is in the episode "Ocean of Fear".
 * Finn can sing in autotune as seen in "The Jiggler" (he sings Baby) and "Freak City" (he sings The Hero Boy Named Finn). Finn reveals to Jake in "The Jiggler" that he has the ability to sing in autotune after swallowing a small computer. However, Finn can also sing without autotuned effects, as demonstrated with numerous other songs.
 * Apparently, Finn can play the flute, as seen in "Prisoners of Love", when he plays a little selection before throwing the flute at Ice King.
 * Finn has claimed to be "all about" several things. In "Freak City", Finn says he is "frickin' all about sugar". Yet, he also explains that he is even more all about feeding hobos. In "The Real You" Finn shouts "I'm all about stupid!"
 * It is possible that Finn has ADHD because of how he flips out at times and can be hyperactive at times.
 * Finn has a female counterpart, Fionna, made by Adventure Time character designer Natasha Allegri.
 * In the episode "Slumber Party Panic" a zombie version of Finn makes a cameo appearance seen here. This could mean that there are two Finns in Ooo, but more likely it was just an Easter egg.
 * Finn likes burnt marshmallows, as demonstrated in the episode "Susan Strong".
 * Finn was raised by Jake's parents, so there is a possibility that Jermaine could also be Finn's brother.

One-time abilities

 * Finn and Jake gained magical abilities in the episode "Wizard" but they have never used those abilities in any other episode. Pendleton Ward later revealed on his Formspring that all of the magic Finn and Jake gained in that episode was contained in their robes, which were later destroyed.
 * Likewise in "The Chamber of Frozen Blades" Finn and Jake gain ice ninja skills, but it's unlikely they will use them again because, according to Adam Muto, "[they] didn't have enough time to commit the incantations and hand positions to memory."

Hat

 * Apparently, Finn has always had (or very close to always had) his awesome hat. In the episode "Memories of Boom Boom Mountain" the viewer can see Finn as a baby wearing the same exact hat, except that it is a smaller size.
 * In the Animated Short, the hole in his hat is half of a circle, instead of a full circle in the cartoon.
 * Finn's hat has a small resemblance of Bueno the Bear from "Barrista" (a short from Pendleton Ward).
 * His hat somewhat resembles Max's hat from Where the Wild Things Are. Also, the two 'ears' on his hat are portrayed as a cat's ears in FusionFall. It's sometimes referred to as a 'bear hat'.

References in other media

 * Finn appears as a playable character on Cartoon Network's TKO where his special moves are Look Out Below (when Jake falls on your opponent) and Sidekick Swing (when Finn grabs Jake's paw and Jake swings him at the opponent) and his super move is when Jake falls onto the opponent with an axe.
 * Finn and Jake were voted best duo of 2010, surpassing Regular Show's Mordecai and Rigby.
 * Both Finn and Jake made an appearance on MAD's "Malcolm in the Middle Earth", but Finn's shirt and pants were miscolored green, his backpack was miscolored blue, and his hat was more pointy, like a cat's head.