The Mushroom Kingdom is the one of the largest kingdoms of Mushroom World. Under the rule of Princess Peach Toadstool, the kingdom has enjoyed and endured both a peaceful and traumatic existence. The former is largely attributed to Peach's ability to rule and the general good-natured feeling that permeates Mushroom Kingdom society.
The latter is largely attributed to the Koopa Troop, a group of turtles who reign over the badlands known as the Dark Land, and their leader, Bowser. However, because of Princess Peach's magnanimousness, the Mushroom Kingdom is able to accept Bowser and his allies within its borders for various kart-racing and sports tournaments. Despite their continued belligerency, the peaceful Mushroom Kingdom never wishes for revenge against the Koopa Troop.