Hungry Kim Jong-un is a really fat guy who is constantly hungry, and is determined to eat everything in existence. He hates UnAmerica and lots of other places, but wants to eat them, as he likes food, eating and also being in charge. He is the hungriest guy ever, in fact, he's as hungry as Baby Yoshi. Some believe they are actually related.
The only person he ever obeys is his father Kim Jong-il, who constantly tells him what to do, and also likes eating. However, after they wouldn't let him rule North Korea, he broke a piece of China off, and turned it into the floating city where he now lives, Big Super Happy Fun Fun Evil China Land. He is now in charge there with his army, away from his angry father.
He and his army have created many weapons as well as as random crud for Big Super Happy Fun Fun Evil China Land, including actual creatures to live in it.