Fionna is an in-universe fictional character and the gender-swapped version of Finn who was created by the Ice King in his fan-fiction. Fionna has many of the same characteristics as Finn. In this episode, Fionna goes with Marshall Lee to a party in the woods. Make sure the character sounds young and tough but still feminine. Fionna does sing in this episode, so please only audition if you are capable of singing in her range.