Humans

 Humans are an endangered species in the post-apocalyptic setting of Adventure Time. It is suspected that Finn is the last human on Earth. Many charicters have marvled at Finn's humanity, like Princess Bubblegum in the episode "Susan Strong." Ethel Rainicorn even went as far as to say that she believed Humans to be extinct. The sparce Human population in the Land of Ooo can probably be attributed to the Mushroom War, a war that took place over 1000 years before the present story line and is thought to have involved the excessive use if nuclear arms.

Known Humans

 * Finn
 * Fionna
 * Susan (Possibly)
 * Old Ladies

Former Humans

 * Marceline
 * Marceline's Father