Fionna the Human

Fionna (previously spelled Fiona and also known as Fionna the Human) is an in-universe fictional character and the gender-swapped version of Finn who was created by the Ice King in his fan-fiction from a strange red glowing inspiration during Ice King's sleep. In the real world, she was created by series character designer Natasha Allegri in a series of web comics and drawings. She and the other gender-swapped characters appeared occasionally in their own segment of the show. She is usually seen in the company of Cake, her own stretchy companion and also adoptive sister. Her enemy is the Ice Queen. She used to have a crush on Prince Gumball and shows signs of attraction towards Marshall Lee, but she's also shown to have a past with Flame Prince. Ice King fantasizes about one day making her real and marrying her.

Appearance
While usually appearing as black dots, her eyes are seen as blue when enlarged. Fionna wears a rabbit-themed hat (similar to Finn's bear-themed hat) with exposed locks of blonde hair and also has teeth missing in a similar fashion to Finn. Unlike Finn, her neck and blonde hair are shown. She also has buck teeth in several episodes, fitting with her rabbit hat. When she is not wearing her hat, her hair goes down to between her knees and ankles. Her outfit includes a teal blue shirt with elbow-length sleeves, a dark blue skirt, and over-the-knee socks with two thin, light blue horizontal stripes at the top. Fionna is a heavier set than Finn (which Natasha referred to as "chubby cute"). She has a green backpack (similar to Finn's) and black Mary Jane shoes.

Personality and character traits
Although Fionna is known to mostly keep her calm, she can be provoked to anger. She will often try to act like one of the guys, so she fits in easily with friends like Marshall Lee or Prince Gumball.

Fionna is a fearless, thrill-seeking, adventure-loving hero who will rescue any prince from the Ice Queen or do any task to better herself or help citizens. She, much like Finn, is also very hard-headed as shown when Cake wanted her to date Prince Gumball and she was stubborn about it.

During the events of "The Prince Who Wanted Everything," Fionna shows a rather ignorant personality towards Lumpy Space Prince. However, this trait may only exist in Lumpy Space Princess's stories, as LSP herself has a very similar personality.

So far, none of Fionna's fears have been introduced and she is known to be very courageous and brave.