Humans

Humans are a critically endangered species in the post-apocalyptic setting of Adventure Time. It is suspected that Finn is the last human on Earth. Many characters have marveled at Finn's humanity, like Princess Bubblegum in the episode "Susan Strong." Bob Rainicorn even went as far as to say that he and his wife Ethel Rainicorn believed humans to be extinct. The scarce human population in the Land of Ooo can probably be attributed to the Mushroom War, which took place about a thousand years before the present story line and is thought to have involved the excessive use of nuclear arms. Another possible cause for the scarce number of humans might be that the inhabitants of Ooo devoured the humans, as species such as Skeletons and Rainicorns have a desire for their flesh.

Note that there are other beings in Ooo (such as Pajama Ninja or Old Man Henchman) that seem to resemble humans. However, Finn and the other characters do not recognize them as humans. According to the show's writers, these characters should be referred to as humanoids or mutants.

Known humans

 * FinnCAP12.png|right|123px|Finn's father in the [[Farmworld timeline.]]
 * Fionna (fictional)

Deceased humans

 * The Commander and Private actors from the movie Heat Signature.
 * Abraham Lincoln
 * Betty

Hybrid humans

 * Stormo (by DNA)
 * Farmworld Marceline (Half human half demon)

Humans that ceased to exist

 * Farmworld Finn (Finn Murton)*
 * Mrs. Murton
 * Mr.Murton
 * Choose Bruce
 * Destiny Gang
 * Big Destiny
 * Trommy

Known former humans

 * Ice King (formerly Simon Petrikov)
 * Marceline (former half human bitten by a vampire)
 * The Lich (mutated by the Great Mushroom Bomb)
 * Farmworld Finn (As Ice Wizard Finn)*