Valsak was the High Captain of the Dark Brother's army. He led the siege against Lerellim and oversaw the death of the High King, allowing the Dark Brother to rule the known world. Although fiercely devoted to the Dark Brother, in the period immediately after the Dark Brother's victory, Valsak seemed to grow more lenient in his handling of the Dark Brother and his enemies. He prevented a group of raiders from slaughtering a farmer and burning his land immediately after the siege of Lerellim. While he did so on the grounds that the army would make use of the food the farmer grew, his lieutenant, Gersner, saw this as a weakness.

However, Valsak sealed his fate during the siege of Oldivor's fortress. His sense of honor, long buried while in service of the Dark Brother, began to re-emerge. He gave Oldivor the opportunity to surrender and serve the Dark Brother. When Oldivor refused, Valsak's men entered the fortress through a magic portal. After fierce fighting, the defenders of the fortress fell. Valsak ordered five men released, charging them to tell everyone they met of the fall of the fortress.

After this victory, Valsak privately admitted to Gerner that he was growing to admire their enemies. Gersner informed the Dark Brother, who brought Valsak before him as a prisoner. Raging that he had not stamped out nobility in his enemies simply to have it grow among his men, the Dark Brother condemened Valsak to an eternity of torture, in the same cell as Oldivor. Gersner was promoted to High Captain.