The Titan was discovered by the ancestor of the royal family long before any of the Titan alive during Xenoblade Chronicles 2 were colonized. Mor Ardain soon became the home of one of the most influent power in Alrest and even more after the destruction of Torna and the nation of Judicium. 10 years before the game, the empire expanded its territory thankw to a war against the Gormotti and from here, Mor Ardain was no longer the only major Titan under Ardainian control. It is said during the game that the raising temperature of the Titan is due to it reaching the end of its life. During the attack on the World Tree, Amalthus nearly kill it by forcing it to release enormous quantities of energy through its chest to attack Torna and the party but after Amalthus' defeat and The Architect's death, Mor Ardain fuse with the other Titans into a giant landmass.
Both the Japanese and English names allude to one of the seven deadly sins featured in the christian religion, pride, the former from the Latin word and the latter from the Scottish Gaelic word mór-àrdan.