Marshall Lee (full title Marshall Lee the Vampire King), is the gender-swapped version of Marceline, created by the original series designer, Natasha Allegri and featured in "Fionna and Cake." He is feared by Cake like Marceline was feared by Jake.
Marshall Lee supposedly has the same abilities as Marceline, since his screen time showed him floating.
His hair is shorter than Marceline's but he has a matching permanent bite mark. He initially wore a grey plaid shirt, but now wears a red and black plaid shirt. He also wears dark blue jeans, and brownish-white sneakers.
Though Marceline has circle-shaped eyes, his eyes are rectangular. Unlike Marceline's forked, snake-like tongue, Marshall Lee's tongue is rounded.
Personality-wise, Marshall Lee should be similar to Marceline.
- He and Marceline both have regular electric bass guitars, as seen in the openings.
- Rebecca Sugar said that she fought for Marshall Lee to have a few lines (such as "Whoa, Fionna! You're wearing a dress? That is Cra-azy son!), but they were cut for time. She wanted him to be voiced by Dante Basco. 
- Marshall Lee floats leaning backwards, back to the ground, and knees bent whereas Marceline floats, knee back, chin up, and leaning forwards.
- Marshall Lee had about 10-11 seconds on screen.
- In an interview with Pendleton Ward, he stated that if there were another genderbent episode, it would mostly focus on Marshall Lee. In this same interview, Pen also officially addresses Marshall Lee as "Marshall Lee the Vampire King." 
- Marshall had 5 fingers when he gave Fionna the "Rock On" sign, but he must only have 4 fingers like Marceline.
- Some of the artwork depicts him in a gray plaid shirt, which looks similar to the one Marceline wore in the episode Video Makers.
|The full image gallery for Marshall Lee may be viewed at Marshall Lee/Gallery.|
- ↑ http://www.formspring.me/natazilla/q/268222375961570118
- ↑ http://www.formspring.me/MrMuto/q/213804012250627128?utm_medium=social&utm_source=facebook&utm_campaign=sharebutton
- ↑ http://rebeccasugar.tumblr.com/post/9693381246/fionna-and-cake-monday-at-8-adam-and-i-really
- ↑ http://www.forbes.com/sites/davidewalt/2011/11/15/its-adventure-time-pendleton-ward-talks-about-his-hit-cartoon/2/