King Reza

The Guild Wars 2 Wiki has an article on King Reza.

Reza, son of Zoran, was the last king of Orr and like many Orrians, a devout follower of the Five Gods. He reigned during the Third Guild War; as king, Reza tried to protect his people from the wars, and encouraged a greater focus on spiritualism, magic, and the arts. He tried to become a peacemaker during the Guild Wars to stop the ravages of war throughout Tyria, but his efforts were ultimately unsuccessful.

Not only did he fail to stop the wars between Kryta and Ascalon, but the attempt to use Orrian troops to stop fighting elsewhere both increased the war's casualties as well as left Orr vulnerable to the charr invasion. Because of this, Vizier Khilbron, Reza's advisor, invoked a dark incantation from the Lost Scrolls and caused the Cataclysm, sending the entire kingdom of Orr to the bottom of the sea.