Marceline Abadeer is a central character in the animated series Adventure Time. As the Vampire Queen, she possesses a unique blend of vampire and demon heritage, making her over a thousand years old. Marceline is known for her love of music, often playing her bass guitar, and her complex, emotional history with other main characters such as Finn and Princess Bubblegum. Her character adds depth to the series, exploring themes of friendship, identity, and the passage of time.