Marceline the Vampire Queen
She was born to an unnamed human mother (voiced by Rebecca Sugar) and the demon Hunson Abadeer (voiced by Olivia's real-life father, Martin Olson). When she was a child, the Mushroom War occurred, and soon after she developed a father-daughter-like bond with Simon Petrikov (voiced by Tom Kenny), who would become the Ice King which was seen in the episodes "I Remember You" and "Simon & Marcy".