During the time of the First War between the Alliance of Lordaeron and the barbaric Horde, Hjalmar was able to rescue his brother Thargas Anvilmar from imprisonment. When Thargas, Varian, , and were travelling on their way to Ironforge they were attacked by a group of Dark Iron dwarves. When the heroes defeated them their leader, , told Thargas that Hjalmar was captured by the Dark Iron dwarves at Thandol Span. The company then decided to go and rescue him.
At Thandol Span, they found Hjalmar held captive by Dark Iron dwarves under the command of . Balgaras intended to kill Hjalmar by melting the Helm of the Anvilmars onto his face. However, Thargas cut his hand off before he could cast a fire spell, and Hjalmar was thus set free. With his other hand Balgaras tried to light one of the explosives, Hjalmar jumped to prevent it, and was mortally injured by the explosion. Before he died, he gave the Helm of the Anvilmars to Thargas telling him to save Thandol Span. In Hjalmar's name, Thargas killed many Dark Irons and helped save the span.
Thargas referred to himself as the impetuous brother and Hjalmar as the levelheaded one.