The Hierophant was a vampire and a member of the Vampire King's court.
Marceline fought The Hierophant centuries ago when she was on a mission to protect the remaining humans from vampires. When the vampires attacked the humans' ship, The Hierophant avoided the initial fight by disguising himself as Schwabl until Two Bread Tom noticed the dog was wearing boots. Marceline manages to defeat him and gain his shapeshifting powers.
The vampires are resurrected after Princess Bubblegum removes Marceline's vampire essence from her. After a short period, the Vampire King and his court manifest. The Hierophant advocates for a return to traditional vampire ways, suggesting that trying to adapt lead to their downfall originally. When the Vampire King admonishes him, The Hierophant parts ways with the group. He seeks out Marceline in hopes of joining forces to bring down the king.
He soon finds Princess King of Ooo and Crunchy and threatens them until they tell him that Marceline is staying at Bubblegum's cabin. Only Peppermint Butler is at the cabin when The Hierophant arrives, and the vampire is mocked by the butler for being "old-fashioned" when he can't enter the cabin without permission. But soon The Hierophant catches Marceline's scent and follows her and her companions into the woods.
The Hierophant finds and easily overpowers Marceline, Finn, Jake, Bubblegum, and Lumpy Space Princess. But soon Jake figures to shapeshift into a house to contain his friends, which once again the "old-fashioned" vampire can't enter without permission. He tries to negotiate a joining of forces with Marceline to defeat The Vampire King, but when he refuses to stop bloodsucking as a term of the truce he again attacks Marceline and poisons her. Just then, Crunchy stumbles into the scene and accidentally knocks The Hierophant into the Jake House. Uninvited, he dies, and the ill Marceline re-absorbs his shape shifting powers. Later, she absorbs The Moon's rapid healing powers to cure the poison.
As a vampire with magical powers, Hierophant has the ability to shapeshift any part of his body at will. This can be seen in "May I Come In?", when he tries to subdue Marceline. He is also capable of producing poison by shapeshifting into poisonous animals or transforming his body into part of said animal like as a scorpion tail. His shapeshifting powers allow him to obtain the abilities of his forms such as heighten sense of smell (by shapeshifting into an animal such as a wolf) or flight (shapeshifting into a form with wings).
Like most vampires he will die if he is exposed to sunlight or staked in the heart. Since he is an old school vampire, he is incapable of entering a house unless he is invited in and if he enters a house without being invited he will die.
- In "Everything Stays," he is shown to have the ability to shapeshift into a black monster with tentacles, similar to a form that Marceline shapeshifted into in "Go With Me."
- He seems to keep the theme of wearing boots in all of his animal transformations, possibly a reference to the story "puss in boots".
- Similarly, most of his animal transformations seem to be a mix of multiple species, giving off a more beastial or unsettling version of the form he is currently portraying. In particular, his large cat/fox form has a distinctly demonic look, reminiscent of the art style you would see in around 17th century demonology grimoires such as the Ars Goetia and Testament of Solomon.
- He is named after the fifth trump or Major Arcana card in traditional Tarot decks. The Hierophant card represents institutional wisdom, religious teaching, and traditional belief systems. Similarly, Hierophant believes in doing things the old-fashioned way. In the reversed position, the card can represent an inability to adapt, which is what leads to the eponymous vampire's downfall.
- This can be ironic due to his ability to change into anything the situation requires.
- He is playing a balalaika (a Russian stringed musical instrument) in "Vamps About."
- Jake describes him as looking like "a wet uncle."
- He is very much a classical vampire, following ancient rules such as how vampires need to be invited in to a house.