Ke-Pa was the ruler of a tribe of demons from the Underworld who came up to Earth and took over the Valley of Peace, where they terrorized its citizens and laid waste to the settlement, gleefully destroying all who attempted to escape or enter. The peaceful villagers fled for their lives amidst the onslaught, but a young Oogway stood against the otherworldly menace, using his fighting skills in conjunction with the Hero's Chi, a power gifted from Heaven that dwelt within the tortoise's body. Using this mystic life energy to fuel his abilities, Oogway drove the demons back whence they came, the demonic hordes fleeing back to the underworld through a crater atop Jade Mountain.
He used the Hero's Chi to seal the entrance in order to prevent their return, but Ke-Pa remained at large and overpowered the young warrior in the form of a giant dragon. Faster and stronger than his dark brethren, the Demon King took advantage of Oogway's exhausted and weakened state to finish him off as the tortoise collapsed at the foot of a peach tree. But since Oogway dedicated himself to protecting the Valley, the tree in turn chose to protect him by using the powers to Heaven and Earth to re-energize the injured master, enabling him to defeat Ke-Pa. Oogway used his Hero's Chi to trap the dragon-like demon in the body of a mortal pig, rendering him powerless so long as the peach tree lived.
