Marceline is over a thousand years old. In "Memory of a Memory," one of Marceline's memories shows her as a young girl playing near the burning ruins of a city, presumably the aftermath of the Mushroom War.
When Marceline was a teenager, her father ate her fries in the ruins of a diner, as Finn witnessed in her memory. This incident would damage Marceline's relationship with her father, which she would later sing about in her "Fry Song." At a later point in her history, she moved into the Tree Fort (that would later become Finn and Jake's home) with her boyfriend Ash. She would later dump him for selling her prized possession Hambo and for being an all-around jerk.
Pendleton Ward also stated that while Marceline is the Vampire Queen, there is no Vampire King because she killed him.
It's unknown exactly when or how Marceline became a vampire, although she did not have a bite mark on her neck when she was younger.
Marceline is described as a wild rocker girl. Centuries of wandering the Land of Ooo have made her a fearless daredevil. She is a lover of all things exotic and still travels the land often. Unlike traditional vampires, Marceline is capable of sustaining herself on "shades of red" instead of exclusively blood. this means she can suck the color out of something that is red and it loses its hue. She has a mischievous personality and is not intimidated by anything. Despite seeming evil at first, she is more of a trickster, and her 'evil plans' often turn out to be nothing more than harmless jokes and teasing. She seems to have a strained relationship with her father and might sometimes have violent outbursts, shown in "It Came from the Nightosphere."
Marceline's outfit in "It Came from the Nightosphere"
Marceline has light blue-gray skin and long, midnight black hair that reaches to her feet. She also sports two marks on her neck which could be the bite mark that turned her into a vampire. Despite being over a thousand years old, her appearance and personality is that of a late teenager. In the episode "Go With Me", her hair is shaved into an undercut, which reveals that she has pointy ears. She is very thin and is said to be thinner thanPrincess Bubblegum by Natasha, who claims she has a smaller butt. However, Adam Muto stated that it depends who is drawing her. In "Evicted!," the singer of the "House Hunting Song" refers to Marceline as a "sexy vampire lady." She is usually floating in the air but when she stands next to the other characters she is taller than them. In some episodes she appears more voluptuous than in others because she can change her form at will.
Marceline wears different outfits in most of her appearances. According to Pen Ward, her clothing changes from episode to episode because "girls own more than one outfit". She wears blue jeans, red boots, and a light gray tank top in her first appearance. In the episode, "Henchman," she is seen wearing a short, dark gray dress, where the top is ripped and there is a dark pink band going across it. It is noted that this dress is made of Why-Wolf hide.
She also wore purple and gray striped stockings, which she probably bought from a thrift store, under the dress and reddish-purple heels. In the episode "It Came from the Nightosphere," Marceline has her hair in a long ponytail that is tied with a white-purplish band. She has a red and dark gray striped long-sleeve shirt and wears gray-blue jeans that are ripped at the knees. She also wears dark blue flip-flops in the episode.
In the episode "Go With Me" her hair is different than in the other episodes, as she has shaved half of her head and had it cut up to waist length. In this episode she also wears a gray dress, black jeans, and burgundy boots. She wears an open plaid, button-up shirt in "Video Makers," with a T-shirt underneath, she also wears blue pants, sneakers, and sports a gray cap adorned with a picture of a horse. She also had a bun in her hair. In "Heat Signature" she wears a dark red tank top with dark brown pants that are ripped and a pair of black high heel short boots.
In "Memory of a Memory," she wears something similar to a nurse's outfit. She appears to have bangs(in her flashbacks as well). In her latest appearance in "What Was Missing," she is seen wearing a red tanktop and blue jean high waist pants, with boots with studs on the back of them. She wears elbow-high sun resistant gloves and a wide-brimmed hat to protect her from the sun.
Marceline's wolf formMarceline's bat monster form
Marceline's abilities have been shown to go beyond that of a traditional vampire, as she has been shown to possess the powers of levitation, pyrokinesis, telekinesis, invisibility, and necromancy, as well as the ability to shapeshift into numerous monstrous forms, including a bat, a wolf, a reptilian creature, or a tentacled monster.
Marceline's tentacled monster form.Also unlike traditional vampires, Marceline is capable of sustaining herself on "shades of red," such as the color in strawberries, and is not limited to surviving on blood. So far, she has been shown to be vulnerable to sunlight, garlic, and stakes, which are classic vampire weaknesses. Marceline additionally seems to have control of how her long hair moves (However, in almost every episode she has been in, she has brushed a lock of it out of her face, though this could simply be a habit). In "Heat Signature," Marceline reveals more of her powers, such as her ability to turn invisible. Later in that episode, Marceline explains to Finn and Jake that vampires can't defeat ghosts: "It's like a rock-paper-scissors thing."
Aside from her supernatural powers, Marceline is a very gifted musician. She has an incredible singing voice and is proficient at playing her Axe-Bass. She is ambidextrous like Finn, this may have helped her to learn to play her her Axe-Bass with either hand, and may even be able to employ double handed tapping, which would allow her to combine simple rhythm progressions with lead parts. As seen in "It Came from the Nightosphere" she is familiar with the production of chords, showing her familiarity with music theory.
Marceline has three bass guitars, one seen in "Evicted!", a Butterfly Bass seen in "Heat Signature", and her Axe-Bass in "Henchman" and "It Came from the Nightosphere." Although Marceline has three bass guitars, she seems to be a lot more attached and protective of her Axe-Bass.
Though they were initially enemies, Finn and Marceline soon befriended one another. Marceline acts as a bully in her debut episode, "Evicted!," she is impressed by Finn's brave aggression and defiance and chooses to kiss him on the cheek after they fight. Both Marceline and Finn share the same spark for adventure and love of danger and excitement. Marceline is very good friends with Finn and seems to trust him and be very comfortable with him.
One of the reasons Finn and Marceline befriend each other is that Finn saved Marceline's life in "Henchman" when Jake exposed her to the sunlight and threw garlic at her in a misguided attempt to help his friend Finn. However, though they are now friends, Marceline still seems to care about her Axe-Bass more than him, as seen in "It Came from the Nightosphere". In "Go With Me", Marceline makes it clear she does not want to date Finn, but Finn explains that he didn't want to date her either. They go to the movies together, but only as friends. Recently, Marceline has expressed that she does indeed care for Finn's well being. This is exemplified in "Heat Signature," where she becomes more protective of Finn when her ghost friends prank him and Jake too far on what started to be a harmless "vampire initiation".
An avid trickster, Marceline cannot avoid scaring Jake when their two paths meet. Seeing his completely rational fear of vampires, Marceline often teases Jake and intentionally horrifies him when the chance is given. This perpetual bullying comes back to haunt Marceline, however, when Jake refuses to believe in her generally wholesome ways and almost fatally wounds her in "Henchman." Since then the two have seemed to intentionally avoid one another: Jake hides in Finn's pocket when he's with Marceline in "It Came From the Nightosphere". However, later in season two, Jake gets over his fear, and he is often seen hanging out with Finn and Marceline as friends. He might even be fully considered a friend as evidenced in the beginning of "Memory of a Memory", when after the Rag Wizard (Ash in disguise) informs Finn and Jake that Marceline is the one in trouble, he begins running faster, and later in the episode, when they run into the young Marceline when she asks who they are, Finn says "We're Finn and Jake!" then Jake says "We're your friends."
Marceline holds a grudge against her father because he ate her fries, as described in Marceline's Fry song. She also said that she didn't think that her father cared about her or loved her, which was probably more hurtful than the fry stealing. (This was made more explicit in Rebecca Sugar's original draft of the song, widely available on the Internet.) When he steals her Axe-Bass, her hatred of him grows. After learning how she really feels through her song, Marceline's father tells her he loves her, and she says she loves him too. They appear to have reconciled for the time being. However, she still prefers that her father remains in his prison in the Nightosphere, because it is too "emotionally exhausting" when he is around. They have a classic teenage-daughter-to-father relationship.
Marceline has a pet zombie poodle named Schwabl That may have come from the cloud kingdom. Seen briefly in her house in the episode "It Came from the Nightosphere." Schwabl was lying in the living room when Finn and Marceline were doing a song. It walked up and went to another room once Finn started beat-boxing. Pendleton Ward has confirmed that Schwabl was based on his friend Marie's dog Schwabble. Schwabble is a white male poodle that has recently passed away, and is seen on the show as Marceline's dog that roams around her house. There is a small dog door for it in the kitchen.
According to the original series pitch document, Marceline and Princess Bubblegum have a 'friendly rivalry' akin to that of a frenemy relationship. Bubblegum shows discomfort around Marceline and appears to disapprove of her creepy ways, while Marceline simply responds to this disapproval with mock affability, even teasing her with Bubblegum's first name of "Bonnibel" and inability to show someone a good time like her. In "What Was Missing," it is shown that Marceline and Princess Bubblegum used to have an undefined relationship, which was seemed to have broken over a past feud. The two can clash easily, as seen in "What Was Missing" when Marceline sang "I'm Just Your Problem" directed towards her and spat on Princess Bubblegum's jacket in the midst of a heated and highly emotional argument. In the same episode, it is revealed that Princess Bubblegum's stolen item is a t-shirt Marceline gave to her some time ago, hinting at some degree of friendly inclination towards Marceline. The princess says she sleeps in the shirt as pajamas, causing Marceline to blush, something she only does when feeling very emotional, which is visible in a few episodes. This resulted in much fan speculation about the nature of their relationship and Marceline's feelings for Princess Bubblegum.
Ash is Marceline's ex-boyfriend. They lived in Finn and Jake's treehouse together before they moved in. Ash performed spells to impress Marceline and called her "Mar-Mar." Eventually Ash sold Hambo, Marceline's beloved childhood toy, resulting in her becoming enraged and dumping him. In "Memory of a Memory," Ash poses as theRag Wizard and pretends Marceline is under a sleep spell in order to trick Finn and Jake into removing the memory of the breakup. She then falls back in love with him, but once Finn shows and explains the situation, she becomes enraged again and kicks Ash in the groin, followed by a heavy pummeling by her and Finn, and later Jake. He does not seem to respect her, as he only wants her to make him dinner. They seem to share a punk-like style.
It seems that Marceline and Beemo have a fairly friendly relationship, she is seen playing it in "Evicted" and comments on how she thinks it's cute. Also in the episode "What Was Missing" Marceline assists Beemo and proceeds to call it "baby."
Marceline's name is based on Pendleton Ward's friend, Marie, whose middle name is Marceline. Pen described Marie as someone who likes the horror movie "Psycho" and dark clothing.
Marceline's right hand momentarily has an extra finger in "Evicted!" when she shows Finn and Jake the Nut Creatures. She also has an extra finger in Heat Signature while putting ketchup on her first two fingers.