From "Adventure Time with Finn & Jake"

Marceline the Vampire Queen is the fearless queen of all vampires, who has a friendly rivalry with Princess Bubblegum. She has wandered the Land of Ooo for centuries. She is a daredevil, musical genius, very seductive, an owner of many homes (including Finn and Jake's), and despite her careless but also fairly harmless merry-making, she is incredibly dangerous when provoked. The show has hinted that she may have a crush on Finn. She may be a vampire, but she only enjoys sucking out "shades of red" from various things such as fruits and jelly doughnuts.

©Pendleton Ward