[5] Considering himself a hero, Finn has a lust for adventure and swore long ago that he would help anyone in need, but being so full of energy, he has trouble in situations that require him to do tasks other than fighting.
[7][8] In "Billy's Bucket List", it is revealed that Finn's birth father, Martin, is alive, and is trapped in a dimension known as the Citadel, which is a prison for the most dangerous criminals in the Multiverse.
[16] Acting as a confidant and mentor to his energetic brother, Jake has a laid-back attitude in most situations, but loves adventure and will eagerly fight when he needs to do so.
[21] In the second-season finale "Mortal Recoil", after being possessed by The Lich, she was accidentally shattered and returned to life as a 13-year-old due to the doctors' not having enough gum to rebuild her to her proper age, though it appears that her memories have remained intact.
[25][27] In the two-part sixth-season finale, Bubblegum is peacefully deposed after the candy citizens vote to replace her with the King of Ooo (voiced by Andy Daly).
[35] Finn and Jake learned during the events of "Holly Jolly Secrets" that the Ice King was originally a human antiquarian named Simon Petrikov who bought his crown from a dock worker in northern Scandinavia, predating the Mushroom War.
[54] LSP is spoiled, sarcastic, and a narcissist, and is often shown living outdoors with salvaged furniture and appears to be homeless, because she has run away from her parents, who are the king and queen of Lumpy Space.
[60] In the episode "Ignition Point" after asking Finn to retrieve candles from the Fire Kingdom, she inadvertently expressed her dislike of her father; this largely stems from her imprisonment.
[76] Martin ended up briefly in Ooo in "The Visitor" after a malfunctioning space-ship he acquired was redirected to Earth by Grob Gob Glob Grod's sacrifice.
Hunson tries to suck all the souls out of everyone before hearing the song Marceline wrote based on him eating her French fries in the past, managing to make peace with his daughter and before being banished to the Nightosphere.
[89][90] In "All Your Fault", after Bubblegum forgot to take the instructions of creating life with her, the Lemongrabs begin making similar-minded lemon candy citizens out of the food that she sent them.
[90] During the events of "Another Five More Short Graybles" the original Lemongrab becomes an overweight despot after eating part of his clone brother after he accidentally broke their "child" Lemonsweets.
A thousand years after the events of the series, two new adventurers, Shermy and Beth (the latter being a descendant of Jake), climb the tree, which has grown immense since then, and acquire the Finn Sword on top of it.
But Gumbald desired power and wished to profit off Ooo, deciding to get rid of Bubblegum by turning her into a foolish candy being by using "dumdum juice," which he used on his co-conspirators Lolly and Chicle in an act of betrayal.
Bubblegum caught on and transformed Gumbald into an unintelligent punch bowl entity, convincing her to create candy citizens with low intelligence.
[105] In "Gumbaldia", he and his family gather a group of the series' past villains who hold grudges against the Candy Kingdom for their army—including the Squirrel, Ricardio the Heart Guy, Bandit Princess, Samantha the Warrior Dog, Peace Master, Me-Mow, Pete Sassafras, Ash the Warlock, Sir Slicer, Scorcher, Fern the Green Knight, as well as Gunter and a confused Ice King—to begin the "Gum War".
[106] But Gumbald ends up being betrayed by Lolly who turned him back into his punch bowl form in the series finale, "Come Along with Me", so she can make peace with Bubblegum.
[99] He plays a significant role in the series finale "Come Along with Me", being summoned to Ooo in the aftermath of the Great Gum War, where he creates monstrous mutations out of the assembled Candy People armies.
[22] Going into hiding in his snail vessel, the Lich arranged for a bear to trick Finn into giving him the Enchiridion for his master plan: to attach the jewels from the various crowns of power, most of which are worn by the princesses, to the book's cover and create a portal to the Multiverse to reach Time Room and have Prismo grant his wish to obliterate all life.
However, having completely rotted Billy's remains off, the Lich is subjected to the regenerative properties of the Citadel's Guardian and is transformed into a harmless giant baby who is then entrusted to Tree Trunks and Mr.
[34] During the sixth season, Gunter the penguin is revealed be a primordial space demon named Orgalorg, who desired to absorb the catalyst comet.
The glimpses into the future shown in "Graybles 1000+", "Come Along with Me" and Fionna and Cake reveal that Ice Thing ended up outliving Turtle Princess, eventually turning into an insane beast under the crown's influence.
Pig and Tree Trunks adopted the Lich, who had been turned into a harmless baby that they named Sweet P.[76] Billy (voiced by Lou Ferrigno)[109] is, according to Finn and Jake, "the greatest warrior ever".
[9] Susan Strong (voiced by Jackie Buscarino),[29] whose name is later revealed to originally have been "Kara", is a large muscular woman with a mechanic implant on her head.
In the Islands miniseries, Kara came from a human colony and was sent to Ooo by Minerva to retrieve Finn, only to lose her memory and live with the half-fish-like humanoid Hyooman tribe.
[139] After the events of "Play Date", it would appear that Abracadaniel and Ice King have developed some sort of friendship, judging by the fact that the two of them were instrumental in organizing the wizard road trip in "Thanks for the Crab Apples, Giuseppe".
[142] This claim is recanted in "The Wild Hunt" when Huntress Wizard returns to help Finn, who is suffering from a previous trauma, into defeating a creature dubbed "the Grumbo".
In order to protect the entirety of Mars from the second coming of GOLB, he created an artificial intelligence named M.A.R.G.L.E.S., in honor of his wife, that he planned to install on the top of Olympus Mons.
[69] In the eponymous eighth-season episode, Normal Man makes amends with his brother and returns to Mars, remorseful and ready to rule benevolently over his Martian compatriots.
[146] Grob Gob Glob Grod reappears in the sixth-season episode "Astral Plane", wherein they seemingly give their lives up to protect Mars from a crashing spaceship piloted by Martin.