Kiem Sun was born during the Sung Dynasty in China. In 1276, He died during a battle against invading Mongols under Kublai Khan. He was soon found by May-Ling Shen who taught about his Immortality and how to survive. She did, however, regard him as a bad student.

He would meet Duncan MacLeod and the two became friends. The two men meet an alchemist who told them about the Quanla Root which he believed will ensure the betterment of humanity. Kiem wanted to learn how to make the formula, and the alchemist taught him but left out the most important ingredient, believing that the Root would be dangerous in the wrong hands.