|This article is about the character. You may be looking for the episode or the Farmworld version.|
As revealed in "The Visitor" by Finn's biological father, Martin, Finn was supposedly born in a "banana boat" in the middle of the ocean where he nearly fell prey to a host of sea-creatures (and a tiger, by Martin's recollection). However, since Martin seems to be confused when recalling Finn's birth, it is uncertain whether or not his memory is accurate.
It is revealed in "Min & Marty" that Finn was born on Hub Island (one of the human-inhabited islands outside of Ooo) to his father Martin Mertens and his mother, Minerva Campbell. Having been a known con artist, Martin is confronted by an old foe and forced to flee the house with baby Finn while Minerva was at work. Martin brings Finn onto a raft, only to be attacked by the Guardian. Finn and Martin are seperated as a result, with Finn being sent adrift towards Ooo and Martin disappearing.
As shown in "Memories of Boom Boom Mountain," Finn appears to have been abandoned in the woods during infancy. He reveals that he made "boom boom" (Finn's word for defecation) on a large leaf and fell on it. He lay there crying until Jake's parents, Joshua and Margaret, rescued him from the wilderness and brought him to their home. They raised him alongside Jake, who, along with Jermaine, became Finn's adopted brother.
It is revealed in "Susan Strong," that Finn knows nothing of his human parents or any other humans. In "Henchman," Finn states that Jake told him that he originated from a cabbage as a joke. However, Finn later learns about his biological father, Martin, in the episode "Billy's Bucket List" and his biological mother, Minerva, in the episode "Min and Marty."
Status as the last human
- Main article: Humans
Up until "Susan Strong", Finn believes he has never met another human and becomes morose and "soul-searchy" when he thinks about it. However, Finn encounters Susan Strong a member of a tribe of mutants called Hyoomans. However, in "Beautopia" ,it is hinted that Susan Strong is unlike the rest of her tribe and may potentially be another human. In "Dark Purple," Susan removes her hat and reveals she is a human with a device on her head, making her possibly some sort of cyborg. However it is unknown if Finn knew about this.
In "Billy's Bucket List", Finn is told by a deceased Billy that his father, Martin, is still alive and is trapped in the Crystal Citadel. This prompts Finn to go there to free his father in "Escape from the Citadel", making him one of four known humans in existence at the time.
In "Preboot" it is revealed by a "human plus" Dr. Gross that are more humans outside of Ooo. This is further explained in "the mini-series Islands, it is revealed that a large population of lost Humans are located southwest from Ooo and settled in three (previously four) islands but most of them are on Founders Island. After the Mushroom War, humanity on the brink of extinction, was saved by The Founders (a group of human survivors of the war) who moves to the islands where they lived isolated from the rest of the world and after nearly a thousand years of repopulating, are still in existence. Finn, Jake, Susan Strong, BMO came to the islands so Finn can find out about his past and his species.
Finn for the first time saw large amounts of humans (not counting his biological father, Martin, Susan Strong, Dr. Gross, Simon, and the time-displaced, Betty) Finn met his mother, Minerva while on the island. His mother is no longer a human and is now a virtual consciousness (A.I.) due to sacrificing her body in order to treat the human race from a virus. Finn was offered to live on the island but Finn decided to go home to Ooo rather than live with the rest of his species and hopes that the humans will someday leave the islands and venture into Ooo. So after the Adventure Time Mini-Series: "Islands" Finn being "the last human" was completely dispelled. Though in the Islands CN Side, Adam Muto stated that Finn being the last human in the world was never the most important thing about him. 
Although various other humanoids exist in the Land of Ooo, most have been confirmed by the show's creator, Pendleton Ward, to be mutants, such as Penny, Phil or the Old Man Henchman. According to Pendleton Ward's FAQ page, even Finn is mutated in some way.
Appearance and equipment
Finn is a teenaged human. He was roughly five feet tall at the show's debut, but sometime between "The Cooler" and "The Pajama War," he underwent a growth spurt and is currently almost the height of Princess Bubblegum. He is missing several teeth due to his habit of biting trees and rocks among other things.
Although his eyes typically lack detail and appear as small black dots, they are shown to have color in "The Enchiridion!" while Finn is under going Dark Magician's trials. His left eye is green while his right eye is blue, characteristic of the genetic condition heterochromia. However, as stated by lead character designer Andy Ristaino, "That was a special occasion. The heterochromatic effect was a byproduct of him being hypnotized by that guardian dude." He went on to confirm that both of Finn's eyes are blue.
Finn's weight seems to fluctuate between episodes, with him seeming chubbier in some instances than others. Pendleton Ward stated on the "In Your Footsteps" commentary on the Season 4 DVD that his weight depends on how active he is adventuring, along with his diet, so it often changes.
In "Escape from the Citadel," Finn's right arm is actually torn off, and then coated by the blood of a Citadel Guardian, which grows 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, with a green thorn protruding from the palm. This thorn was later revealed in "The Comet" to be part of the Grass Sword sticking out from his skin, as his new arm was made of grass.
In "Reboot," Finn's Grass Sword detached from his arm and fused with the Finn Sword which combined into Fern. Because of this, Finn is an amputee again. However this time there is no flower growing out of where his arm should be and as of "Two Swords" Finn has a mechanical arm.
Finn has blonde hair which is first seen in "To Cut a Woman's Hair," where Finn removes his hat, and long, golden locks of hair flows out. His hair has a glowing sheen and extended his body length, until he cuts it off and gives it to the Tree Witch. His hair slowly begins to regrow throughout several episodes until "Another Way" where it has grown to his shoulders. By "The Lich," Finn has grown his hair slightly longer than in its appearance in previous episodes. However, in the episode "Davey," Finn has shaves off almost all of his hair for the second time so he can disguise himself as 'Davey', but begins to regrow it in "Little Dude," and the episodes after it. In "Puhoy," an adult Finn is shown to have grown facial hair and his hair become curly although since that part of the episode was a daydream it may not be 100% accurate. In "May I Come In?", Finn's long hair is shown to have grown back to around the length it was in "To Cut a Woman's Hair", when Finn takes of his hat while acting as bait to lure out The Hierophant.
- Main article: Finn's hat
Finn typically wears a munsell blue ("color #0093AF") t-shirt, denim shorts, a two-colored 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" (which Joshua calls "nubs") 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" when Penny steals his shorts at the end of the episode. 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.
- Main article: Finn's swords
Finn has had a total of five major swords, plus temporary borrowed ones. (1) He originally favored Scarlet, the Golden Sword. After being first turned into a 4-D Sword and then destroyed by a black hole in "The Real You," (2) Finn is shown using the Root Sword (having a pink/silver blade and a red, twisted "root" handle) as seen in "Mystery Train." Along with this sword, his backpack has a new side strap that can hold the sword while walking. (3) In "Dad's Dungeon," Finn and Jake venture into Joshua's dungeon, built by Joshua to toughen Finn up. There, Finn retrieves the Demon Sword, which uses now as primary weapon. (4) After being first turned into the Grape Sword and then forced to destroy it in "Play Date," he replaces his weapon with the Grass Sword, as seen in "Blade of Grass." However, this too was lost, along with his right arm, after Finn's encounter with his father in "Escape from the Citadel." Though the sword did actually was still in him internally until "Reboot." There have been a number of other swords used by Finn, but all were used only for a short period of time. (5) After Finn's grass sword was destroyed, he acquired the Finn Sword in "Is That You?" It was created by interacting with an alternate Finn from the past, creating a paradox. Finn uses this sword first in "Dentist." However, when the glass on the Finn Sword is broken, Finn ceases to use it for a while and started using the Root Sword again. He started using the Finn Sword again in "Preboot" and "Reboot" however at the end of the two-part episode it was merged with Finn's grass sword creating Fern, making Finn loose his arm again, and permanently destroying the Finn Sword.
- Main article: Finn's crossbows
Personality and traits
Although at times impulsive and aggressive, Finn is a kind, brave, selfless, and righteous boy. His aspirations to become a great hero makes him somewhat of a moral sheriff in the Land of Ooo, as he is willing to help and protect any innocent person or creature. Finn has a very strong sense of responsibility and becomes upset when he is unable to help others. Due to this and being somewhat simple-minded, Finn often feels conflicted when it is unclear whether something is good or evil as exemplified by his dealings with Marceline in the episode "Henchman." Despite his heroic nature, Finn also takes a liking to a "normal life" without any recognition or praise for being a hero and demonstrates this in "Davey."
Finn is also almost incapable of doing anything evil or unjust, and will struggle greatly against doing such things, as seen in several episodes such as taking part in thievery in "City of Thieves" or killing a neutrally aligned ant in "The Enchiridion!." However, Finn undergoes a slight change in "Wake Up" after he realizes that his father, whom he had high hopes of being a great hero, is nothing more than a selfish criminal. This, coupled with the loss of his favorite arm and sword due to his father's selfishness, pushes Finn to the point of wanting revenge. This is shown in "The Tower," where he attempts to go into space by building up a tower so that he could find his father, punch him, and take his arm. However, in the end, Finn learns to control his feelings of revenge with the help of Princess Bubblegum.
While he portrays himself as a rough and tough hero, Finn has a tender side that is capable of love and compassion, as shown by his boyhood crush on Princess Bubblegum and his brotherly relationship with Jake. Finn is also able to act like a gentleman when it comes to ladies. However, Finn seems to hate romantic scenes to the point of vomiting as seen in "Go With Me." However, Finn demonstrates growth in accepting romance and physical love as he willingly kisses Princess Bubblegum in "Too Young" and his latest ex-girlfriend, Flame Princess, in "Burning Low." His tolerance is seen again near the end of "Dream of Love," as he is no longer disgusted by Tree Trunks and Mr. Pigs' passionate kissing. Finn's care for his friends makes him very protective of them as demonstrated when Tree Trunks almost gets killed in the episode "Tree Trunks" and Jake in "The New Frontier." Overall, Finn is a very kind and selfless person who is always putting the safety of others above his own. Jake comments on his adopted brother by saying that "he is a good kid with a kind heart."
In the episode "Rainy Day Daydream," it is shown that Finn believes that "imagination is for turbonerds who can't handle how kick butt reality is" and that he finds real life to be better than anything imaginary. Finn then refuses to use his imagination until he has to reactivate Jake's "bombastic personality" in his imagination land, (which was just a basic gray and white empty plane hinting that Finn is not very imaginative). However, this is disputable when the gnomes harness the energy from Finn's imagination in the episode "Power Animal" despite it being inhabited with a few dainty creatures such as Bellamy Bug. The gnomes state that Finn's imagination is powerful enough to effect the real world (like Jake's but to a lower degree) and turn on Jake's imagination.
Finn can also be very stubborn; such as in "Memories of Boom Boom Mountain," "Wizard," "Dungeon," "Rainy Day Daydream," and especially in "Another Way." This is likely a reason why Finn is often determined to work without taking the easy way out as seen in "Business Time" and "The Real You." Finn can also be easily tricked, as in "The Eyes" when Jake convinces him that the giant hawks would take the horse to a land of sunshine and love stuff and take care of him. He can get overly angry and yell as in "Trouble in Lumpy Space" and "Tree Trunks," but immediately feels guilt and remorse and apologizes when he can. Finn is also quick to try and resolve problems that he may have caused, such as when he caused Flame Princess to get hurt by the Ice King. Finn is also empathetic and this was developed when he was an infant since no one (except Jake's parents Joshua and Margaret) helped him.
As a courageous warrior and a fearless thrill-seeker, Finn enjoys putting himself in the midst of danger simply because he enjoys a challenge as shown in "Jake Suit." However, he is also shown to have several fears. In "Another Way" and "King Worm," he demonstrates a fear of clowns. Also, in "King Worm," he shows a fear of Bubblegum calling him too young. In both "King Worm" and "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. Other fears that Finn has are the Ghost Lady, King Worm, and the Lich. Finn's fears change in "Billy's Bucket List," after he destroys Fear Feaster, a manifestation of his fears, with his grass sword while attempting to go into the ocean to fulfill Billy's wish. The Fear Feaster's death seems to have eliminated all of Finn's fears, or at least his fear of the ocean.
Despite being mischievous from time to time, Finn is a very kind-hearted person. It's shown multiple times that he shows clear concern for others, even for those who have willingly hurt him, such as in "The Enchiridion," he returned to the giant his dollar (note that this was was the very same giant who ate his beloved brother Jake and even kept insisting that he was dead). Furthermore, he shows clear contempt for anything that is done out of immoral reasons.
Finn is also shown as willing to sacrifice himself in order to save others, as seen in the episode "James". With all other plans of escaping the Oozers showing no promise, Finn offered himself as a sacrifice without hesitation, so the others may escape. Though, He was knocked out and Princess Bubblegum convinced James to be the sacrifice instead.
Despite his age and appearance, Finn seems to be quite strong and athletic; he can be seen wrestling full-grown Marauders, the large grass ogre Donny, and a general variety of monsters and creatures several times his size. Finn is also capable of lifting up Princess Bubblegum, as shown in "Mortal Recoil" when he picks her up and puts her in her bed, and capable of lifting up Marceline as seen in "Daddy's Little Monster." In addition, he is able to pick up a tree and hit Barb, a giant spider, in "Web Weirdos." In "Another Way," Finn is able to run long distances while carrying a giant cyclops' eye. Lastly, in "Dad's Dungeon," when Finn stabs the Evil Monster in the eye, he is able to lift it up slightly off the ground and flip it into the pit. Being the size it is, the giant Evil Monster should have weighed at least several tons, thus showing Finn's strength. Finn is also agile as he can jump very high and even make his arms and legs bend in inhuman ways, as during the Science Dance and when he uses "spaghetti limbs" (waving his arms and legs, which Jake can also do). In "The New Frontier," it is shown that Finn can make fire only with his hands.
Finn is very tolerant to pain as in "No One Can Hear You" he merely says "whatever," when the Stag breaks his legs. Finn can also endure high temperatures, as seen in "Jake Suit" as he allows Jake to dip his head in lava, and also in "Rattleballs," when he sits in a mini-barbecue. This may be because he is already accustomed to heat from his relationship with Flame Princess. Also, in "The Lich," he is able to break the Enchiridion on his knee without any sign of pain, demonstrating considerable strength and resilience. He even tries to teach Jake how to tolerate pain in "Jake Suit," when he says, "just pretend like every bruise is a hickey from the universe." Finn seems to have impeccable balance, as he is able to balance himself on two wheels in his wheelchair in the episode "No One Can Hear You." However, he refers to it as "skills." Finn is known to have deuteranopia, a form of heredity dichromatism that makes it difficult to distinguish green hues from red, as shown in "Red Starved." As this is a sex-linked genetic condition inherited on the X chromosome, Finn must have inherited the condition from his mother.
Magic wise Finn has obtained an immunity to electricity as well as electric based attacks thanks to magic spring water in Flute Spell this ability seems to have stuck with him as we see him display the non effectiveness of electricity in Preboot against a giant electric eel and again in The Light Cloud against the Great Guardian.
Finn has the ability to mentally fight psychic abilities. The first time he shows this during the Lich's attempt to control his mind. The second time was against Goliad, as he was constantly able to manipulate his own thoughts in order to avoid revealing the plan to defeat her, allowing Princess Bubblegum to create Stormo. Finn can focus for a very long time as shown in "Still" when he spends hours telepathically summoning an Astral Beast. As demonstrated in "The Creeps," Finn can lock unwanted memories in "the vault," which is later seen in "King Worm." However, this is considered a normal human ability that occurs where certain memories are removed from the consciousness if is too painful or traumatic for them to recall. Finn also has the ability to read and write, and he can also do simple math.
Finn is proficient in several forms of combat, including hand-to-hand, magic, and swordsmanship. When using hand-to-hand combat, he is an aggressive fighter, combining some forms of martial arts or his amazing swordsmanship skills. Finn prefers overpowering his opponents, but he is also quick enough to understand an opponent's weakness or using his environment to win a fight. He also received training from the old gumball robot Rattleballs which dramatically improved his sword skills and his reflexes to greater levels.
Besides combat, Finn displays many other impressive abilities in handicraft. He has some origami skills, as shown in "Ricardio the Heart Guy," in which he makes Princess Bubblegum a paper crane, as well as in "Marceline's Closet," in which he makes a paper airplane. In addition to that, Finn is shown to be able to construct a sculpture of the Candy Kingdom from his saliva for Princess Bubblegum in "The Real You." Finn is also somewhat gifted at constructing simple machines, such as the catapult in "The Witch's Garden."
Finn enjoys singing; after swallowing a tiny computer, he gains the ability to Auto-tune his voice on command, although he can sing without it as well. Apparently, Finn can also play the flute, as seen in "Prisoners of Love," where he plays a short lick before javelin-throwing it at Ice King. Unfortunately, the flute falls apart before it could hit him. Because of this, Finn is not seen playing the flute until "The Lich" as Farmworld Finn and near the climax of "Finn the Human" when he shoves it into Tromo's nose. He is also very good at beat boxing as seen in "It Came from the Nightosphere" and "What Was Missing." In "Gut Grinder," Finn tries to play Jake's viola, but Jake says he stinks. Jake even imitates his foot prints and said "I'm Finn the Human, and I stink at viola." However, during "Death in Bloom," Finn panicked over what instrument to pick, supposedly because he could not play any of them, and settles for sleigh bells. In the episode "Go With Me," Finn is seen playing the lute. In "Daddy's Little Monster," he is seen playing the tambourine.
Finn is very good at playing a video game called Adventure Master, which he and Jake play on BMO from time to time. Finn can also spit very long distances, as he demonstrates in "Evicted!," when he spits on Marceline, "My Two Favorite People," when he spits on Tiffany's face, and in "Web Weirdos," when he spits on birds flying overhead, while suspended upside down on a giant spider web. In "Dungeon," one of the trials that Jake says Finn would have breezed through is a spitting competition against a goblin-like creature. In "Burning Low," Finn is shown to be able to spit water incredibly high into the air. In "Who Would Win," Finn showers Jake with an abnormal amount of saliva through spitting. He also handles his sword with his right hand, suggesting he may be ambidextrous, able to use both hands with equal skill. This is also seen in "Frost & Fire," where Finn writes with his left and right hands and, occasionally, both at the same time. Finn is able to cook, although he leaves this task mostly to Jake. However, in "In Your Footsteps," it mentions and shows him making Finn Cakes.
Finn and Jake gain magical abilities in the episode "Wizard," but they never use those abilities in any other episode. Pendleton Ward later revealed on his Spring that all of the magic that Finn and Jake gained in that episode was contained in their robes, which were destroyed. Likewise, in "The Chamber of Frozen Blades," Finn and Jake gain ice-ninja skills, but it is 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." Finn seems to speak Latin (as evident in "Morituri Te Salutamus,") although this may be caused by the magical powers of Fight King's arena. In "Daddy's Little Monster," for the first time, he becomes an antagonist by wearing the Nightosphere amulet, although it is only temporary. In "The Tower", Finn gains a new mental arm with the ability to interact with the physical world. His emotions seem to cause this, along with the ability of telekinesis. Since it was linked with his emotions, it exploded into a huge arm of spikes when he confronted his "dad," and disappeared when Finn's animosity abated.
Finn is twelve years old at the start of the series and progressively grows older relative to the passing of time in real life. As of "Mystery Train" (March 14, 2011), he is thirteen years old. Finn is shown going through puberty throughout the series. This is seen whenever when he screams as his voice cracks. Finn's voice is noticeably deeper at thirteen than it was at age twelve as a result of his voice actor aging. Episodes with early production codes have Finn with a very childlike voice such as "The Enchiridion!," "Prisoners of Love," "Evicted!," and "Ricardio the Heart Guy."
In an interview in early 2012 (at the end of season three), Pendleton Ward stated that Finn is fourteen.
After the episode "Earth & Water," it was revealed that Flame Princess was fifteen years old. Assuming that they are both the same age (in "Incendium," Flambo and Jake states that she was Finn's age), Finn is then fifteen as well. Finn was eventually confirmed to be 15 years old in the second half of Season 5, according to Adam Muto, and in "The Comet," he is sixteen years old.
- Main article: Finn's relationships
Alternate Universe Finns
- Main article: Farmworld Finn
This is Finn Mertens' alternate universe form. He came into existence because of the wish that Prismo granted normal-universe Finn in the episode "Finn the Human," and he was also in "Jake the Dog." Here, he has a pointed nose, wide eyes, a robotic arm, and a munsell blue sweater instead of a shirt. He was later the bearer of the Ice King's crown after using it to save his family.
In the episode "Puhoy," Finn travels to a realm full of pillows where he cannot escape and eventually starts a new life, becoming an adult and elder. Elder Finn loses his right arm and replaces it with an artificial one.
- Main article: Shoko
In "The Vault," it is revealed that the strange, amorphous, ghost that has seemingly been haunting him is Shoko, his former self in a past life, who was horribly mutated before her death. Finn completes her dying wish by returning Princess Bubblegum the amulet that Shoko had stolen from her in the past.
Disguises and forms
In the episode "Go With Me," Finn is shown wearing a "lute suit" provided by his friend, Jake, in his attempt to convince Princess Bubblegum to go to the movies with him. It is also shown later in the episode when he tries to get Marceline to go to the movies with him.
Magic Fist is the alter-ego of Finn and Jake that first appears in "Wizard Battle." He is not a real wizard; he only enters the Wizard Battle to prevent Princess Bubblegum from potentially having to kiss the Ice King on the lips as the prize for winning the battle. He wears a blue eye mask, electric-green hood, and a large red robe. Finn is the head, while Jake is the body. See the gallery section for more images.
Finn is transformed into a cat by the Grand Master Wizard when Finn forfeits the Wizard Battle; however, Finn was able to break out of it after becoming enraged by Abracadaniel's decision to take the kiss from Princess Bubblegum.
In "The Creeps," Finn wears a black tuxedo with a blue trimmed collar that has a split tail end. He also has a matching blue bow tie, a gray vest, a brown and tan fox mask over his characteristic hat, and brown "fancy gloves."
Giant Foot Finn
In the episode "Freak City," Finn is turned into a foot by Magic Man who posses as a beggar. As a foot, Finn has great difficulty moving at first, and only musters the effort to make himself fall over. Finn is upset at his physical handicap while Jake tries to make him realize that being a foot is a blessing. Finn is unconvinced, and later becomes motivated to return to his original body after discovering that Magic Man has turned many others into body parts as well. After working with the other victims, Finn seemingly defeats Magic Man as the Super Freak. Magic Man restores Finn and the rest of the freaks to their original bodies.
Zombie Finn looks like Finn, and apparently appears in "Slumber Party Panic." Zombie Finn appears in the bottom left corner of the first window to be broken when the zombies break the barricades. Zombie Finn also appears in the Adventure Time game, Rhythm Heroes. In the game, Finn appears as a zombie just like in "Slumber Party Panic." He seems to be controlled by Marceline in the game, and he is next to two other zombies, a cupcake and a candy heart. He was most likely added as a joke or Easter egg.
In the episode "Trouble in Lumpy Space," Finn turns into a Lumpy Space person after giving the antidote to Jake so that he can return back to his normal body.
By doing this, he turns into a Lumpy Space person as well. Lumpy Finn hates Lumpy Jake.
In "Daddy's Little Monster," Finn puts on the Nightosphere amulet to rescue Jake and Marceline from the Nightosphere. This causes him to transform into a huge, monstrous, demonic form similar to Hunson Abadeer. Afterwards, he tries to pull Jake and Marceline back into the world, but stops after Hunson reverts Finn back into his original form.
Paper plate demon Finn
In "Daddy's Little Monster," Finn disguises himself as a demon in order to sneak into the Nightosphere. He puts on his red pajamas, cuts a paper plate and puts it on his face, and tapes forks to his hat.
Hug Wolf Finn
In the episode "Hug Wolf," Finn is hugged by the Alpha Hug Wolf on a full moon, causing him to transform into a Hug Wolf during the night. When he is in this form, he must go on a hugging spree to fulfill his hug lust. However, in the morning, he does not recall anything he did in the night before. As a Hug Wolf, Finn has shaggy gray fur, heart-shaped hands and feet, and wears torn clothing. He is cured when he hugs the Alpha Hug Wolf which cures her as well.
Prince Finn of the Grasslands
Although not directly used by Finn, in the episode "Incendium," Jake introduces himself as 'Baron of the Grasslands' to Flame King and calls Finn 'Prince Finn'.
In the the titular episode, Finn disguises himself as "Davey" in an attempt to hide from his followers. Davey eventually evolves into his own character, possibly hinting that Finn temporarily develops a multiple personality disorder.
The Finn Sword is created in "Is That You?" after Finn sacrifices an alternate version of himself to save Prismo. After visiting a much more elaborate version of Prismo's Time room, created as a "Plan B," Finn makes a choice to save Prismo by creating a paradox that vaporizes his dream world duplicate. Instead of turning to dust, Finn's body turns into a sword, dubbed the Finn Sword by Prismo.
During the first five seasons, every alternate reality/past life/dream version of Finn is shown to have no right arm, or have a robotic right arm. These include Shoko, the no-Lich universe Finn in the fifth season premiere, and the older Finns in "Puhroy", "Mortal Folly", and "Dungeon Train". The real Finn loses his arm in "Escape from the Citadel", though it regrows in the episode "Breezy". However, it is technically not his arm, but the Grass Sword, meaning that it is somewhat prosthetic, despite having skin. In "Reboot", Finn tries to prevent the Grass Sword from attacking Susan, but accidentally causes it to merge with the Finn Sword and create a Grass Person, leaving Finn without a right arm yet again. As of "Two Swords", Finn has a robot arm, just like the alternate versions of him.
After being turned into an egg by Magic Man in the episode "You Forgot Your Floaties," Finn falls into a bowl of flour where he was then accidentally baked into bread by Betty Grof. Finn breaks out of the oven and stumbles onto Jake who had previously been transformed into soup by Magic Man. Finn then proceeds to smash Magic Man's transmutation apparatus which disrupts Magic Man's transmutation with Glob's helmet.
Main Article: Grass Finn (Fern)
When the Grass Sword combined with the Finn Sword in the end of Reboot it created a humanoid Grass Finn which is shown to be Finn Swords mind inside a grass body called Fern the Human. Finn has many doubts about it. It is technically the same Finn, because the Finn Sword is Finn from another timeline turned into a sword.
Every episode except the following:
- "Fionna and Cake"
- "Thank You"
- "BMO Noire"
- "Lady & Peebles"
- "I Remember You"
- "Jake the Dad"
- "Mystery Dungeon"
- "Simon & Marcy"
- "Finn the Human"
- "Jake the Dog"
- "BMO Lost"
- "The Suitor"
- "The Party's Over, Isla de Señorita"
- "One Last Job"
- "Sky Witch" (No Lines)
- "Bad Timing" (No Lines; Cameo)
- "Lemonhope Part 1"
- "Lemonhope Part 2"
- "Sad Face" (No Lines; Cameo)
- "Little Brother" (No Lines; Cameo)
- "Thanks for the Crabapples, Giuseppe"
- "Joshua and Margaret Investigations"
- "Everything's Jake"
- "The Cooler"
- "Gold Stars"
- "Dark Purple"
- "On the Lam" (Pictured)
- "The Gift That Reaps Giving" (short)
- "Everything Stays"
- "Summer Showers" (No Lines; Cameo)
- "High Strangeness" (No Lines, Cameo)
- "Jelly Beans Have Power" (No Lines, Cameo)
- "Hide and Seek"
- "Min and Marty"
- "Bad Little Boy"
- "The Prince Who Wanted Everything"
- "Princess Day"
- "The Diary"
- "Friends Forever"
- "Be Sweet"
- "Sow, Do You like Them Apples" (short)
- "Cherry Cream Soda" (mentioned)
- "Broke His Crown"
- "Lady Rainicorn of the Crystal Dimension"
- "Five Short Tables"
- "Daddy-Daughter Card Wars"
- "Baby" (with Jake)
- "Never Ending Pie Song"
- "Key Song"
- "Pump It Up!"
- "The Hero Boy Named Finn"
- "Empathy Song" (with Donny)
- "Fry Song" (with Marceline)
- "Forest Guy"
- "The Decorating Song" (with Jake)
- "Goblin Song"
- "Computer Song" (with Jake)
- "Susan Strong"
- "Bears" (with Jake & Party Pat)
- "The Stuff Song" (with Jake)
- "Sing 'Cause Yo Mama Said" (with Jake)
- "Oh, Baby Yeah" (with Jake)
- "Puncha yo Buns"
- "We're Finn and Jake" (with Jake)
- "Wizard Battle"
- "Bubblegum's Blueprint track" (with BMO & Marceline)
- "A Song About Noodles"
- "My Best Friends in the World" (with Jake, Princess Bubblegum, BMO & Marceline)
- "Sleepy Puppies"
- "Extremities Song"
- "All Gummed Up Inside"
- "Political Rap" (with Jake)
- "Dungeon Crawl"
- "I Just Can't Get Over You"
- "Oh, It's Just My Luck!"
- "Princess Song"
- "Rap Bear & Finn's Rap" (with Rap Bear)
- "Baby's Building a Tower into Space"
- "Lost in the Darkness/Love" (with Princess Bubblegum & Breezy)
- "Der Hölle Rache kocht in meinem Herzen" (with Jake)
- "We're Plants" (with Jake)
- "Food Chain" (with Princess Bubblegum)
- "Everything is Falling into Place"
- "I Look Up To You"
- In the Cartoon Network Live Action Promo "What Time Is It?" Finn is portrayed by Christopher Kramme.
- In Legends of Ooo, it is seen that Finn has a telescope which he uses to spy on Princess Bubblegum and Flame Princess.
- Finn is technically still the King of the Goblins; the goblins believe his scapegoat, Whisper Dan, to be him.
- Finn has a fictional female counterpart: Fionna.
- One of Finn's catch-phrases is being "all about" something. 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!"
- In "Dad's Dungeon," it is revealed that Finn cries rarely; only in such devastating situations, such as death or heartbreak (or when he poops as revealed by Jake in Memories of Boom Boom Mountain).
- Finn and Jake frequently use math terms as catch-phrases and at times censors for curse words. However, they are shown to be terrible at math as confirmed in the episode "Slumber Party Panic." (Examples of these words include: mathematical, rhombus, algebraic and math). This has seemingly been abandoned as the show progresses.
- Finn's favorites have been stated throughout the series.
- When Finn is wearing his doctor suit in "His Hero," he has three Scientific Parasites in his pockets.
- In "Jake vs. Me-Mow," Finn carries his adoptive mother's music box in his pack and knows her lullaby by heart.
- "Bad Little Boy," "The Prince Who Wanted Everything," "Princess Day," "Evergreen," "The Diary," "Friends Forever," "Be Sweet," "Orgalorg," "Varmints," "Cherry Cream Soda," "Broke His Crown," "Lady Rainicorn of the Crystal Dimension", "Five Short Tables," and "Daddy-Daughter Card Wars" are the only episodes where Finn did not make an appearance.
- In the early version of "Daddy-Daughter Card Wars," he was initially going to appear at the beginning of the episode, but this was likely cut for time in the final version. 
- Stormo is a creation partially made from Finn's DNA from the episode "Goliad."
- Flame Princess is Finn's first and former girlfriend. Jake referred to Princess Bubblegum as Finn's ex-girlfriend in "In Your Footsteps," but Finn replied that they "never went steady."
- It appears that Finn is the only character so far who ages consistently.
- In the beginning of the series, Finn's voice is more high pitched, but later near the latest episodes, Finn's voice is a bit deeper from puberty.
- Finn, along with Jake, are the only two characters shown to die and come back to life.
- There is a secret GPS implanted on Finn's ear by Princess Bubblegum, as stated in "Lady & Peebles."
- Besides Tree Trunks' pies, Finn also likes Wildberry Princess's meat pies.
- Finn likes to make lists to remember things, like in "The Real You" and "Five Short Graybles."
- In "Dungeon Train," Jake says Finn is about 5' tall.
- Finn may have some driving experience. In "Candy Streets," Finn drives Jake after he turns into a car. (This may only be true if Jake wasn't controlling himself.)
- According to the Official Adventure Time Encyclopedia, Finn got his name from Joshua and Margaret as they initially believed that he was a Mudfish as they knew very little about humans.
- In "The Red Throne," Finn says that he has been learning a bit of piano.
- In "Lemonhope Part 1," it is shown that Finn has been taking classes at a school run by Princess Bubblegum, one of his classes being geometry.
- In "Dentist," it is revealed that he actually knows his full name given at birth, which is "Finn Mertens," not counting his alternate universe self in "Finn the Human."
- His Demonic Form is most likely a reference to Slenderman.
- In the episode "The Vault," it's revealed that one of Finn's past lives was a comet. This could have some connection to the Catalyst Comet. This was confirmed in "The Comet," as the Catalyst Comet was in fact one of Finn's past lives.
- In all of Finn's alternate variants, he eventually gets his right arm removed.
- Finn has begun to grow facial hair, but BMO plucks it out every morning as shown in "All's Well That Rats Swell".
- In an Adventure Time comic, Jake questioned how Finn puts random things in his backpack, one thing is a pack of pens. This may be a reference to Finn's original name.
- Finn's last name is a Dutch variant of the name Martin, which means 'warrior'.
- Finn's hat has a similarity to the hats Helpers wear, as seen on his mother Minerva's head.
- Finn McCool was an adventurer and hero of Irish mythology. "Finn" is actually a nickname meaning "blonde."
- In the original short, Finn was named "Pen."
- In Issue 9, it is revealed that Finn had been called "Pen" in the original short because of his love for pens. Although originally, he was most probably named after the creator of Adventure Time, Pendleton Ward. A future Finn then takes his red sleeping bag when him and Jake leave to help Lady Rainicorn, also leaving a note of advice telling Finn to use his real name. This, however, is most likely non-canon.
- In the pilot, Finn is voiced by Zack Shada. However, in the series, he is voiced by Zack's younger brother, Jeremy Shada.
- Jeremy Shada can make Finn's voice crack when asked during episode recording to better represent his youth and growth.
- In the original storyboard of "The Lich," it is revealed that Finn's father was unlawfully imprisoned years ago in the Crystal Citadel, which houses the most dangerous criminals from other dimensions. This does not appear in the final product; Finn's father's existence is not revealed until "Billy's Bucket List" and is not seen until "Escape from the Citadel."
Appearances in other media
- Finn appears as a playable icon in Geometry Dash (2.1 Update) You can also color him to look like Finn.
- Finn and Jake appeared four times on the series MAD. See References in other media for a detailed description.
- 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, Jake, Princess Bubblegum, Lady Rainicorn, Ice King, Stanley the watermelon, and the Reaper are characters in the game FusionFall, in which the player helps Finn save two princesses, get shirts from Stanley, and train with Finn in the petting zoo (Generator Rex).
- Like most of the main characters, Finn is an Exosuit in the game Project Exonaut. His suit is in the "Banzai Squadron" (red) faction.
- There is a licensed Halloween costume of Finn.
- In the then-popular Facebook game called "Pet Society," there was a Finn Costume labeled, "Odyssey Boy Costume."
- Finn is a playable character in the game FusionFall Heroes.
- Finn and Jake make a cameo appearance in the Futurama episode "Leela and the Genestalk."
- Finn has a playable kart in the Cartoon Network app, Formula C Cartoon; it is one of the free karts given to the player at the beginning.
- A child in a Finn costume appeared in the Halloween episode of South Park "Nightmare on Face Time."
- Finn and Jake had a balloon depicting them in the Macy's Thanksgiving Day Parade in 2013-2015. The balloon retired after the 2015 Macy's Thanksgiving Day Parade.
- In the app Lil' Alchemist by Kongregate, there is a card in the Huntress event that looks like Finn but has different colored clothes and skin. This character is called "Adventure Kid."
- Finn is a playable character in Adventure Time Battle Party.
- Bart dresses like Finn in The Simpsons episode "Treehouse of Horror XXV."
- Finn's name appears in the Steven Universe and Uncle Grandpa crossover, "Say Uncle."
- Finn's birthmark is looks like a flaming sideways teardrop located in a really weird part of his body, as described by Finn in "Crossover."
- Finn is a playable character in the 2015 video game Lego Dimensions. His level pack was released on September 27th, 2016.
- Finn also shows up in Adventure Time: Hey Ice King, Why'd You Steal Our Garbage?!! not only as the main character, but, in the 3DS version, imputing the Konami code that shows an 8-bit version of Finn and Jake dancing with Pendleton Ward while he sings the secret song.
|The full image gallery for Finn may be viewed at Finn/Gallery.|