Flame Princess' younger brothers are the sons of Flame King and the brothers of Flame Princess. Not much is known about the two. One of them looks similar to the Flame King as he wears a crown and clothes resembling Flame King's, whereas Randy, whose name is revealed in "The Cooler," does not wear a crown.
Flame Princess's younger brothers are roughly half the height of their older sister. The smaller of the two is orange in color and wears a crown and a ruby-embossed suit. The larger, Randy, is red in color and wears a body suit resembling a coal.
So far, Flame Princess' younger brothers have only appeared together in the episode "Jake Suit." They are introduced when Flame Princess invites Finn over for dinner with her "less evil family members." When Finn takes off his clothes to do the "Baby Finn Song," the brothers gasp and stare with their mouths hanging open, although they appear less offended than Flame Princess' older brother.
In the episode, Randy appeared along with his older brother and aunt in the discussion chamber. When Flame Princess told them that they need ideas, Randy told her that he would do his best to help the Fire Kingdom, but Flame Princess disregard his attempt and apprised him that he is only with them for safety purposes and to continue to eat his snacks. Later, Randy sent out a message to Princess Bubblegum before the ground of the discussion chamber let out another cool air pocket. He managed to escape with the others without getting hit, with the exception of his aunt.
- They, their older brother, Neptr, Prince Huge, and Box Prince are the only princes in the show who are not gender-swapped characters.
- Randy is the third character in the series named Randy. The first was Randy from "Davey," and the second was Tree Trunks' ex-husband Randy.