Brock is a the blacksmith of Asgard and the person who would forge Lady Death's new sword, Nightmare.
During the events of The Crucible he is one of the first Asgard citizens to witness Lady Death, the savior, put on a show of power to the disbelieving townsfolk. He and Grimnir watch drunkenly amused from a doorway, neither has been sober since Odin's death. Later they watch Lady Death's antics in the court of Queen Frigga.
He attends the battle in the north at the Frost giants strategically important location and loots the scene while his friend Grim is more interested in Lady Death, even wanting to aid her in battle. He becomes braver as time passes and helps defend Asgard on the battlefield but when the battle comes to a tragic end he jumps into a barrel and hides.
Following the battle he recovers Darkness, Lady Death's sword, and with Grim and Frigga goes below ground to his forge. He melts down Darkness, Lady Death's sword, countering the spells and then reforging it with spells of his own and some he took from an alchemist. Grim has his face swathed in bandages and helps his friend by fetching the unusual shaped mold for the sword. Brock tells him that Odin commissioned the mold but not the sword, that it was to wait until it was needed.
He takes the finished sword to Lady Death who bonds wit the blade and uses it to defeat Genocide. Once vanquished she be comes increasingly reclusive, spending time with the sword that writhes with energy and brings her to the decision to leave this now peaceful land and retake her place in Hell.