Candy Kingdom

The Candy Kingdom is a kingdom that was made and is ruled by Princess Bubblegum. It is made entirely of sweets and sugar, and is the most popular and recurring kingdom in the series. The Candy People are the citizens that live there, most of them resembling some sort of candy or other sweet. Some of the known Candy People include Mr. Cupcake, Chocoberry, The Earl of Lemongrab, Chet, Peppermint Butler, Starchy, Nurse Poundcake and Dr. Ice Cream, Princess Bubblegum (?), Manfried, and Cinnamon Bun. Parties and major celebrations are thrown constantly here; this may be the Candy Kingdom's culture, or Princess Bubblegum's own positive personality.

Princess Bubblegum's Castle
This is the main center/castle of Candy Kingdom where their ruler Princess Bubblegum lives, along with other Candy People.

Physical composition
Nearly everything in the Candy Kingdom is made of some kind of candy, including the ground which is made of peanut brittle as shown in "Susan Strong." The exception is that the dirt is just regular dirt as seen in "Too Young."

It was revealed in "Burning Low" that the Candy Kingdom owns territory that isn't candy, as Princess Bubblegum was collecting taxes from Finn and Jake's Tree House.

Despite being a kingdom with living candies, it still has candies and sweets to eat. The distinction (as Finn explains in "Susan Strong") is that "You can't eat the ones that talk! They're special...they got aspirations."

Military
It is unknown whether or not the Candy Kingdom has been in any war or battle, however, the candy military seems to have advanced significantly over the course of the show. In the episode "Susan Strong," it is shown that the Candy Castle has an armory full of candy weapons. In the episode "Princess Cookie" it was revealed the Candy Kingdom has candy helicopters, which seems to be a large technological advantage over any other kingdom, although the true efficiency of candy weapons has yet to be tested.

The Candy Kingdom also maintains the Banana Guard, whose primary role appears to be that of a police force. The Gumball Guardians also act as a main line of defense, appearing quite often just outside the walls of the Candy Kingdom.

Trivia

 * As implied by Jake in "Susan Strong," the Candy Kingdom military is rather ineffective, only winning the battle against the Hyooman tribe by sheer luck because the Marshmallow Kids were accidentally set on fire by Jake when he sneezed into the fire. However, it has seemed to advance in Season 4, with candy cane rifles and candy helicopters.
 * The Candy Kingdom is guarded by the Guardians of the Royal Promise. They are shown to attack evil in the episodes "Slumber Party Panic," "Mortal Recoil," and "The Lich ."
 * Adam Muto has said that the Candy Kingdom is a "princessipality" due to the fact that it is ruled by a Princess instead of a King or Queen.
 * Finn nearly caused its destruction three times. First, when he opened a black hole in "The Real You." Second, when he showed Susan Strong the kingdom and she brought the other Hyooman tribe members to eat it. Third, when he released wolves in Princess Bubblegum's room in "Go With Me," endangering Princess Bubblegum's life.
 * Finn mentioned it had a church, signifying that there is religion in Ooo.
 * Like in most cities, there is a "bad" part of town. It can be found behind Princess Bubblegum's castle as seen in "Apple Thief." The Candy Tavern is located there, and it is full of criminals.
 * The Candy Kingdom is home to the Candy Kingdom Mental Hospital, where the very old and the mentally ill reside, playing games. It appears to be run by Doctor Princess.
 * Gunter and his magic penguin army (temporarily) conquered the Candy Kingdom (and the rest of Ooo) in "Reign of Gunters"
 * It was revealed in "All Your Fault" that Princess Bubblegum made the Candy Kingdom.