Finn the human (Real name: Finn Mertens), known as Finn to most characters is, along with Jake the Dog, a fictional character and one of the main cast of the American animated television series Adventure Time created by Pendleton Ward. He is voiced byJeremy Shada in most appearances. The character made his debut in the original pilot, wherein he was named Pen and voiced byZack Shada, Jeremy's older brother.
The character has been met with largely positive critical reception.
Finn debuted at 11, but over the course of the show he has aged, and is now 16. Finn sets off on magical random quests around the Land of Ooo killing anything evil as shown in the Enchiridion episode and would not harm any non evil, not even an innocent ant. Having a strong moral code, Finn swore that he would help anyone in need and often performs heroic feats to save the day; however, starting after season 3, Finn's enthusiastic nature becomes more toned down as the series progresses, suggesting he is both maturing and developing as a character as he ages. As shown in "Memories of Boom Boom Mountain", Finn appears to have been abandoned in the woods during infancy. He reveals that he had made "boom boom"—a euphemism for defecation—on a large leaf, fallen on it, and lay there crying until Joshua and Margaret, Jake's parents, rescued him from the wilderness and took him in to raise him alongside Jake, who became like a brother to him. As such, Jake is also Finn's adoptive brother. In "Henchman", when Finn is asked about his parents, he says Jake told him that he came from a cabbage, in jest. In the episode "Susan Strong", Finn states that he knows nothing of his human parents or any other humans. He is one of the few characters in the series (along withFlame Princess) who ages regularly. According to the episode "The Vault", Finn has had a number of past lives. In "Red Starved" it is revealed that Finn is color blind, believing that an emerald was a ruby. In the Season 6 opener "Escape From the Citadel", Finn lost half of his right arm, up to his elbow, from which a flower protruded. He later regains his arm, now as a prosthetic, in the episode "Breezy".
Finn is a 5 foot tall teenage human. He has several missing teeth, blond hair, of which the length differs due to occasional haircuts. His eyes appear black from a distance, but according to lead character designer Andy Ristaino, they are blue. He wears a white bear hat, denim shorts, and a light blue T-shirt. He also has a green backpack, black shoes, and socks rolled down to his ankles. Finn is a teenage boy who is currently 16 years old (according to Season 6 finale, The Comet), average height and weight. His arms and legs are very thin, but he has a wide torso. He is missing several teeth because they often face monsters that hit him in the face, also he often bites rocks and other hard objects. These teeth are sometimes round or pointed and constantly changing place, depending on the occasion. In the episode "The Enchiridion!" it can be seen for a moment that his left eye is green while his right eye is blue, as if he has heterochromia. However, Andy Ristaino confirmed that this was a "special occasion" and that in fact both eyes are light blue, which is not visible to the naked eye. He also points out in that episode that Finn had a small round nose but this is considered more of an error or humorous scene.
In "Escape from the Citadel", Finn loses his right arm after it was pulled off after an attempt to reach his father, which is then coated by the blood of a Citadel Guardian that makes it grow into a small flower. He later got his arm back in the episode, "Breezy," where the flower stub matured into a tree and broke away like a cocoon, revealing a new limb.
According to Jake, Finn is about 5 feet tall (1.50 meters). This is revealed in the episode "Dungeon Train", in the second half of the fifth season. In the 23rd episode of the sixth season, The Pajama War, it is seen that he has grown considerably, being almost as tall as Princess Bubblegum, who, biologically, is many years older than Finn.
Finn typically wears a munsell blue ("color #0093AF") t-shirt, denim shorts, a two-toned lime green circular backpack, rolled-down white socks, and a pair of black shoes. Finn's most prominent attire is a white hat with two "ears" sticking out on top that covers his entire head minus his face. The hat is inspired by a character called Bueno, a bear from a Pendleton Ward comics. Finn can occasionally be seen in variations of his standard outfit. In "Ocean of Fear," his footwear appears to be black booties with white cuffs. In "It Came from the Nightosphere", Finn has a small pocket sewn onto his shirt that he carries Jake in. This appears again in "Davey" where he uses it to hide Jake while Finn steals the keys from the guards as he breaks the former out of jail. During "In Your Footsteps," the Bear wears Finn's clothes, which suggests that Finn has multiple sets of the same outfit, including his hat. However, in "Little Dude," when Finn's hat comes to life and is set free, Jake tells Finn, "Okay, let's go skin an evil bear," which may imply that Finn only had one hat.
Aside from his normal outfit, Finn can be seen wearing a cream-yellow sweater in colder areas such as the Ice Kingdom but currently wears his pink sweater made by Princess Bubblegum. In "Holly Jolly Secrets Part II," he wears a dark blue sweater with Christmas decorations on it and a green scarf. Finn also wears white briefs that make their first appearance in "City of Thieves". In "Who Would Win," he was shown to wear a different pair with red elastic. Finn sleeps in red footie pajamas that appear in many episodes, but in the animated short, he sleeps in a red sleeping bag in his regular clothes. In the series, the sleeping bag is beige.
Status as the last human
Until the episode "Betty", Finn was the only known human in the Land of Ooo. A common theory explaining the etymology of his name includes the Spanish word "fin", meaning "end". Another possibility is that his name is Irish, Finn being a name of a mythological Irish hero, whose name is derived from "fionn", the Irish language word for blonde; Finn the Human is blonde as well. The cause for him being the last human is alluded to by Finn and many other characters as "The Great Mushroom War", which is practically a nuclear war that wiped out the majority of humanity. Up until the character "Susan Strong" is introduced, Finn believes that he has never met another human. When Finn encounters Susan Strong, the other members of Susan's tribe of "Hyoomen" are revealed to be mutants, and Susan's identity as a human or mutant is left ambiguous. In the episode "Beautopia", it is hinted upon that Susan may also be human, but it is not confirmed. The businessmen that Finn meets in the "Business Time" are also human, though they have been mutated over time. In the episode "Her Parents", Lady Rainicorn's parents (Bob and Ethel) attempt to eat Finn because they thought they would never get the chance to eat one, as they believed humans were extinct. Finn's female counterpart Fionna the Human is a human living in the Land of Aaa, though it has no official name; however, she exists only in a parallel universe conceived by the Ice King, when he wrote a fanfiction based upon his life and experiences with Finn and Jake. There are many other characters in the show that appear to be human but have been confirmed to be humanoids or mutants. In the episode Be More, the character Moseph "Moe" Mastro Giovanni, who is the creator of BMO, appears to be a human, but is revealed that he has replaced most of his body parts (except the skin) with artificial ones, which makes him virtually a cyborg. In the episode "Betty," Betty Grof (known as Simon Petrikov's former fiancee) was brought from the past into Ooo, and later in "Escape From the Citadel" Finn's father, Martin, is introduced, making Finn no longer the last human. In a series «The Visitor» of Finn's father, Martin said that "once he was sent on an important mission on which he could not take it", this phrase is an allusion to the existence of people.
However, during the season 6 finale event, two episodes and their events bring a return to Finn's status as the last human on Ooo. In "You Forgot Your Floaties", Betty Grof becomes Magic Man's apprentice and in return for helping Magic Man, he promised her a cure for her fiance. Things go awry and at the end of the episode, Betty takes Magic Man's hat, thus becoming a wizard and losing her status as a human. Additionally, in the finale episode, "The Comet", after Finn learns of his past and declines an offer to become a higher being, his father, Martin, takes the offer and ascends to another level of being, likely bringing an end to his human form.
Finn is currently 16 as revealed in the season 6 finale episode, "The Comet". At the beginning of the series, Finn was a 12-year-old boy who is supposedly the only known human in the Land of Ooo. During the episode "Mystery Train", Finn turned 13; it has been stated that the episode first airing date (March 14) is Finn´s birthday. After season 3 ended,Pendleton Ward stated in an interview that Finn was 14. Finn was 15 years old in the second half of Season 5, according to Adam Muto. In the Season 6 finale, "The Comet", Finn reveals that he has reached 16 years of age. Adventure Time is one of the few cartoons where time passes regularly, instead of characters staying the same age for the run of the show or aging through time skips. For these reasons, Finn likely turned 17 on March 14, 2016.