During the Thousand-Year War, Surt led a legion of demons and jotunn from Muspell to burn down the world of Midgard. His attempt was thwarted by the Aesir and he was forced to retreat back to his world.
In A.W. 400, Surt attempts to burn the world again, but instead of the Aesir, Surt was opposed by the lone Warrior Thanatos. For 10 days and nights, Surt and Thanatos engaged in a battle of epic proportion. Their strikes and blows sundered the earth and shook the heavens. On the last day, Thanatos manages to defeat Surt and seal the jotunn into Midgard's crust, over which a shrine is built to maintain the seal. His minions scattered all over Midgard, taking the form of Normans to lay low and await the return of their lord and master.