Top Row: Lumpy Space Princess, Lady Rainicorn, Gunter (the penguin)
Second Row from Top: Marceline, Ice King, Princess Bubblegum, Lemongrab
Third Row from Top: Flame Princess, Finn the Human, BMO and the Snail, Peppermint Butler
Bottom Row: Jake the Dog, Tree Trunks.
The American animated television franchise Adventure Time features a cast of fictional characters created by Pendleton Ward. The first series in the franchise, Adventure Time revolves around the adventures of protagonists Finn the Human (voiced by Jeremy Shada), a teenage human boy, and his best friend Jake the Dog (voiced by John DiMaggio), a dog with magical powers to change shape and grow and shrink at will. Finn and Jake live in the post-apocalyptic Land of Ooo, and travel the land while they adventure. Along the way, they interact with the other main characters of the show: Princess Bubblegum (voiced by Hynden Walch), the Ice King, Simon Petrikov (voiced by Tom Kenny), and Marceline the Vampire Queen (voiced by Olivia Olson). The second series Distant Lands, follow these characters along with the Peppermint Butler "Pep" (voiced by Steve Little), while Fionna and Cake follows Fionna Campbell (voiced by Madeleine Martin), Cake the Cat (voiced by Roz Ryan), Prismo the Wishmaster (voiced by Sean Rohani), Gary Prince (voiced by Andrew Rannells), Marshall Lee (voiced by Donald Glover), and the Scarab (voiced by Kayleigh McKee), along with a returning Kenny as Simon Petrikov.
This list only includes the main characters of the show, as well as major recurring characters (otherwise known as supporting characters) who are featured across several episodes of the series. Characters which are credited as guest stars or one-off characters are not included.