Marshall Lee is a fictional character from the animated series Adventure Time, appearing in the gender-swapped universe episodes. He is the male counterpart of Marceline the Vampire Queen and is known as the Vampire King. Marshall Lee is charismatic, mischievous, and enjoys teasing others, especially his friends. He plays the bass guitar and has a laid-back, adventurous personality. In the series, Marshall Lee adds a unique dynamic to the cast, showcasing the creative world-building of Adventure Time.