Character
Fionna Campbell
Fionna Campbell in Adventure Time: Fionna and Cake (2023), played by Madeleine Martin.
Fionna Campbell, also known as Fionna the Human, is the main protagonist of Adventure Time: Fionna & Cake, and was previously an in-universe fictional character and the gender-swapped version of Finn who were part of a fanfiction the Ice King made from a strange red glowing inspiration during his sleep. She and the other gender-swapped characters would occasionally appear in their own segment of the show.
Read more about Fionna Campbell on Adventure Time Wiki at Fandom