Flint is the son of Flame King and the brother of Flame Princess. He first appeared in the episode "Jake Suit," in which Flame Princess introduces him as her older brother who works in the military. He reappeared in "The Cooler," urging his sister to blow up the Candy Kingdom as sugar burns hotter and faster with extra calories, and stating that they are "trash" people. By the end of the episode, he was still urging his sister to do that, to which she responded with a pat on his shoulder.
Similar to his sister and her father, he is short-tempered and impatient. In "Jake Suit," he became enraged when Finn took off his clothes and performed the Baby Finn Song in front of his family. He seems to dislike when someone is intolerant to his family and is a little overprotective of Flame Princess.
- He, his younger brothers, Neptr, Prince Huge, and Box Prince are the only princes in the show who are not gender-swapped characters.
What are you doing in front of my family?!
This is a nightmare come true for me, sister.
Blow up the Candy Kingdom!