Flame Prince

Flame Prince is the gender-swapped version of Flame Princess. He was created by Natasha Allegri in her artwork. While he has never appeared in any episodes of the series, he has a main role in the Adventure Time with Fionna and Cake comic mini-series. Here, it is revealed that he is a feral child who lives with a Fire Lion pride. When the Ice Queen kidnaps the babies of the pride, Flame Prince goes after her, only to be defeated and have a heated salt crystal inserted into him that eats away at his body heat. After being rescued by Fionna and Cake, he ended up getting reduced to a small flame ball-like creature.

Appearance
He has fire-like hair styled up and a big red jewel on his forehead. He also has yellow skin and pointed ears. He wears an orange and red suit and matching boots, each with a red jewel on it.

When he is turned into a small fire creature by the Ice Queen, he has the shape of a small fire ball, retaining the red jewel on his forehead.

Trivia

 * Even though Flame Prince was created, he has not yet been in a "Fionna and Cake" episode.
 * The picture where Fionna is over Flame Prince, drawn by Natasha Allegri, bears strong resemblance to the scene in Burning Low where Finn saves Flame Princess from being extinguished.
 * Even after the rest of his body turns blue in the first issue of the comic, the crystal in Flame Prince's forehead stays red. The crystal also stays with him after he is reduced in size.
 * In "Adventure Time with Fionna and Cake Comic Issue 5," Flame Prince's costume is made by Cake.
 * In the original Adventure Time (not gender-swapped version), since Flame Princess is Finn's girlfriend (prior to "Frost & Fire"), Flame Prince can be assumed to be in a relationship with Fionna (if he has been shown in an episode).