Finn

Finn (or Pen, from the pilot episode, or full title: Finn the Human) 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 laid there until Joshua and Margaret (the mother and father of secondary protagonist Jake) rescued him from the wilderness to raise him along with Jake. In "Henchman" when Finn is asked about his parents, he says Jake told him that he came from a cabbage in jest, implying he doesn't know anything about his true parents.

Appearance
Finn is a 12 year old human with very thin, flimsy limbs who wears a white hat, which he has proclaimed is "awesome," that covers all except his face with two "ears" sticking out on top. 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.

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.

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 &quot;The Witch's Garden."

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. Jake is apparently a very big influence for Finn. In "Rainy Day Daydream", Jake playfully says to one of the imaginary girls, "I want to have your baby." Later, it was discovered that Finn said the same thing while singing the Key Song in the episode "Dungeon".

Lady Rainicorn
Finn became friends with Lady Rainicorn after Jake wanted to hang out with both of them at once. 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 his closest female companion, 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 his unrequited love. Though the princess is seemingly oblivious to Finn's affection, she shares a connection of unconditional love with the hero and often calls on him for any royal need. Their romantic relationship has yet to surpass a thankful kiss on the cheek, yet Finn always eagerly hopes to win the princess over with his heroic deeds. Beyond unrequited love, Finn and Princess Bubblegum also 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".

Quotes
See Finn/Quotes

Trivia

 * In the pilot episode/short, Finn was 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.
 * 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 or wells.
 * It is unknown if Finn remembers how he was abandoned, if he has any siblings, or remembers his parents.
 * 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 "Memories of Boom Boom Mountain", Jake reveals that Finn still cries when he poops.
 * Finn's hat has a small resemblance of Bueno the Bear from "Barrista" (a short from Pendleton Ward).
 * Finn is left-handed when writing or drawing, but uses his sword with his right hand. In "Business Time", he used his sword with his left hand for a short period of time, and then switched back again. In "The Jiggler", Finn uses his left hand to draw, so it appears that Finn is ambidextrous, which means that he can use both his hands with equal ability.
 * 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.
 * 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 Formspring that the all of the magic Finn and Jake gained in that episode was contained in their robes, which were later destroyed.
 * Finn and Jake can accurately tell what time it is by looking at how the sun affects the trees, stated by Pendleton Ward.
 * In the Animated Short, the hole in his hat is half of a circle, instead of a full circle in the cartoon.
 * 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".
 * Confirmed on Pendleton Ward's Formspring, Finn has blonde hair.
 * Finn has a crush on Princess Bubblegum, and whenever someone says "Finn," "Princess Bubblegum," and "crush" in the same sentence, he growls and blushes fiercely.
 * 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 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, demonstrated by the Never Ending Pie Song and Key Song.
 * In "Freak City", Finn claims he is "frickin' all about sugar". Yet, he also explains that he is even more all about feeding hobos.
 * Confirmed on Pendleton Ward's Formspring Finn's sword is made of gold.
 * It is shown in "Crystals Have Power" that Finn is sad that Tree Trunks exploded.
 * 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.