Thorim served the titans as guardian of Ulduar and the Terrace of the Makers, and protecting the pacts between the races of frost.

After betraying the Pantheon, Thorim's brother Loken tricked him into betraying his frost giant allies by murdering his wife, Sif, and blaming it on the frost giant king. Thorim was enraged, striking out at his allies and then settling into a long stupor.

Many years later, Thorim discovered the truth. With the aid of players serving the Sons of Hodir, Thorim recovered his weapon and his armor, then brought war to his treacherous brother. However, it proved to be an elaborate ruse perpetrated by Loken to lure Thorim away from the Temple of Storms, where proximity to his dark master granted him the power to overcome Thorim's attack. Thorim and his proto-drake, Veranus, were captured and taken to "new dwellings".

Thorim's power is said to have been invoked once, and that it turned a whole continent into dust.