

In "Marcy & Hunson," this person is revealed to be Hunson.

In " Everything Stays", Simon, who has almost transformed into the Ice King permanently and is thus leaving to isolate himself, assures a young Marceline that he has arranged for someone else to take care of her.

In " I Remember You", in a flashback, a young Marceline is seen saying "Daddy? Daddy where are you?!" indicating that, for some reason, her father wasn't with her after the apocalypse. At some point in the past, Hunson was separated from Marceline for a considerable period of time in the aftermath of the Mushroom War, during which she was cared for by Simon Petrikov before he was fully transformed into the Ice King. In the full version of Marceline's fry song, there exist the lyrics "Daddy, why did you leave me, You created me, So don't you wanna see me?". He says he is proud of her, and smiles, so they may have worked out their issues. Marceline's father confessed that he only wanted to be very proud of her, and Marceline told him that she wanted him to be proud of who she wants to be. Later in the episode after Finn and Jake free Marceline from the Nightosphere amulet's control, she is shocked that her dad fooled her into wearing it he had told her that it would grant her wishes, rather than forcing her to be the demonic ruler of the eponymous realm. Finn is reluctant because he still thinks her father is evil, but she assures that he is "cool," perhaps meaning that they are on better terms. In " Daddy's Little Monster", Marceline asks Finn and Jake if they want to party in the Nightosphere. Hunson and his daughter have a tender moment where they affirm their love for each other before Finn traps him back in the Nightosphere. Their relationship begins to heal when Finn plays Marceline's heartfelt " Fry Song" out loud.

Marceline is embarrassed when Hunson hears her song Hunson would eventually be imprisoned in the Nightosphere and Marceline wouldn't talk to him until the events of " It Came from the Nightosphere", which occurred presumably many hundreds of years after the incident with the fries. They have had a consistently strained relationship since Marceline's childhood, culminating in him eating her fries when she was a pre-teen, whereafter Marceline felt that he didn't care about her.
