Kaien (カイエン, Kaien?) is a historical character from Final Fantasy XIV. He was the last king of Doma before falling under the Garlean Empire's control. His son, the crowned prince Hien is the main character of Final Fantasy XIV: Stormblood main scenario, fighting to liberate the lands.
Kaien is said to be one of the greatest swordsman. However, he was defeated by Zenos yae Galvus.