- This is an article about wizards as a species. For a list of all magic users in Ooo, see Category:Magic Users.
Wizards are a species in the Land of Ooo. The creators of Adventure Time have suggested that "wizard" is the actual species of two characters: Ice King and Ash. When asked whether Ice King was a human, Natasha Allegri responded that he was a wizard. It was later revealed that the Ice King did in fact use to be human before he discovered the ice crown, which changed his body and drove him insane. Allegri's statement is still factually true, however. Adam Muto has stated that Ash is a wizard, "Not a vampire or demon." Note that in both cases, it was only implied by the nature of the question (not directly stated) that "wizard" is a species.
While there are many other wizards/witches in Ooo, their species has never been directly stated. Some wizards such as Rock Wizard and Dimension Wizard are obviously different species, so it would be incorrect to assume that all characters called "wizard/witch" actually belong to the wizard/witch species.
Wizards appear to mostly reside within Wizard City, a hidden location only accessible by a wizard saying the password, "Wizards rule." Many wizards seen on the series demonstrate a competitive, elitist attitude, explicitly forbidding non-wizards from participating in Wizard Battle or entering Wizard City, and punishing those who do. Wizards often seek to prove their power over others through such competitions as Wizard Battle, or by creating exclusionary clubs such as the Secret Society, which are based around unearthing secret magics from ancient schools. In "Thanks for the Crabapples, Giuseppe," it's shown that there are multiple secret societies within the wizard community, which often flaunt their "secret wizard handshakes" and mock non-members. Ice King, Abracadaniel, and several other lower-class wizards start their own society in that episode based on their shared experiences on a road trip.
All wizards have a concept of magic, madness, and sadness in them as revealed in You Forgot Your Floaties. Betty Grof is researching the trinity in order to find a way to harness them to save Simon. Magic Man says there is a way to transfer magic from one being to another and says that magic and science are different.