Background

Marceline Evelyn Abadeer was born just before the Mushroom War to a demon lord named Hunson Abadeer and a human woman named Elise, being one year older than her sister Sarah and three years older than her twin siblings Marsha and Damian. Abadeer is the ruler of the Nightosphere, a Hell-like demon dimension, and subsists on the souls of sentient beings. For her early life, she lived with her mother and sister in a trailer. But when Elise began suffering from an illness, she attempted to keep it hidden from Marceline so as not to worry her. She had her draw a map of the land to get to a secret “club house” where there was supposedly a party happening. However, as Elise’s health slowly worsened further, she told Marceline to go to the hide-out on her own, where she was left alone, believing her mother had abandoned her due to her demonic powers.

Eventually leaving the hide-out, Marceline found herself alone in the wreckage of the old world. During this time, Simon Petrikov—the man who would become the Ice King when he was overcome by the power of his crown—found Marceline in the ruins of a city and gave her a stuffed animal named Hambo to cheer her up. Seeing her alone, Simon took it upon himself to look after and raise the young Marceline, developing a loving father-daughter relationship with her. Although the crown ruined Simon’s mental health, forcing him to leave Marceline alone.

During this period in her life, Simon presumably somehow managed to reunite Marceline with her father, only to be disgusted by his cold and heartless ways. Although she attempted to tolerate his evil and selfish antics, she eventually severed all ties with Abadeer after she discovered him eating fries that she had bought for herself.

In the following years, Marceline roamed the Land of Ooo. She starts to hunt down the remaining vampires of Ooo and has a dog named Schwabl. She also realizes that due to the powers she inherited from her demon father, she has the ability to suck the souls and gain the powers of the vampires she kills and absorbs. She eventually befriended a tribe of humans. These humans wore animal hats, to protect against vampire bites. At first, they were understandably fearful of Marceline, however, after following them for some time, a member of the group, Two Bread Tom, sat down and played the guitar to the few remaining members of their group. Marceline heard this, and sat down behind a bush to play the same song Tom was playing. Because of this, they viewed Marceline in a brighter light, and realized she was just trying to keep them safe. She became their guardian and ally, and she helped them kill vampires, who had taken over much of the land. The human tribe was attacked by the Vampire King while repairing a boat, and Marceline defended them. However, when she tried to fight the Vampire King herself, he pinned her down and bit her. Although she eventually managed to slay him, she was turned in the process, becoming the last vampire in Ooo.

At some point, Marceline met Princess Bubblegum, the sovereign of the Candy Kingdom. Marceline gifted her a Rock T-shirt during a music performance and they became romantically involved. It was also around this time that she was reunited with her siblings while also meeting her other sister Sarah, all of whom ran away from their father. In addition to finally getting to know her sisters, Marceline and Bubblegum would often avoid official royal meetings and explore the Candy Kingdom’s elaborate rock candy mining complex, although as time went by and the mounting stress of running the Candy Kingdom became more and more demanding, Bubblegum started pushing Marceline away. This reached its climax when Marceline accompanied Bubblegum to the Glass Kingdom who had asked for her help defeating a dragon attacking their kingdom. However, Marceline didn’t take the whole thing seriously and bugged Bubblegum for attention causing her to lash out and tell her to go home. Hurt, Marceline sung an angry song to her about how she didn’t care about her or her “stupid Candy Kingdom”. Marceline’s song managed to defeat the dragon, but this signified the end of her and Bubblegum’s relationship. The animosity between them would last for many years.

Later, she began a romantic relationship with a magician named Ash, who she met at one of her shows. After Marceline had a falling out with her siblings over Ash, Marceline and Ash would move into the Tree House, but their relationship would come to an end after Ash sold Hambo, her most prized possession, to Maja the Sky Witch. Despite realizing that her sisters were right about Ash, Marceline didn't reconcile with her siblings for hundreds of years.