Humans

Humans are a critically endangered species in the post-apocalyptic setting of Adventure Time. It's 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 very 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 weapons. Another possible cause for the scarce number of humans might be that the inhabitants of Ooo devoured the humans, as Peppermint Butler and species such as Skeletons and Rainicorns have a desire for their flesh.

Note that there are other beings in Ooo (such as Phil 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. It should also be noted that the last humans with Finn as the only confirmed example show a striking difference in appearance to the alternate timeline and presumably unmutated humans, which have regular sized eyes with visible whites and pupils, and more prominent noses.

Known humans

 * FinnCAP12.png
 * Fionna (fictional)

Deceased humans

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

Humans from the Farmworld timeline

 * Finn's Mom
 * Finn's Dad
 * Finn's Baby Brother
 * Choose Bruce
 * Farmworld Marceline (Half-Human)
 * Destiny Gang
 * Big Destiny
 * Trami
 * Tromo
 * Unnamed Destiny Gang Members

Known former humans

 * Simon Petrikov (now Ice King)
 * Ice Queen (fictional)
 * Randall N. Byron (now computer software; Comic only)
 * Business Men (now mutants)
 * Marceline (now vampire)

Hybrid humans

 * Jay &amp; Bonnie (Human/Pillow hybrid)
 * Stormo (by DNA)
 * Adventure Tim (Human/Dog hybrid; Comic only)