Darius quit his job at Grafton Steel after growing discontented with the lack of response to the workers' concerns about workplace safety. He believed his resignation would deal a severe blow to the company, as he considered himself "the best chemist this side of the Mississippi" and believed they would never be able to replace him. Darius' brother, Billy, also worked at Grafton Steel; Darius tried to convince him to resign as well, but Billy refused, citing his need to support his family. Billy later died after he fell from a catwalk into a vat of molten steel.
Darius swore revenge against Grafton Steel for Billy's death. Grief pushed him to investigate the company in-depth, uncovering a network of shadowy connections, kickbacks, farcical inspections, and general bribery between Grafton Steel and the United States government. Afraid of company surveillance, he moved out to a cabin in the woods. Gradually growing paranoid and unhinged, he began to view everything surrounding him as a threat. This caused him to shoot a hiker he thought to be a company spy and even booby-trap his cabin against local wildlife, fearing they were trained by the company to spy on him as well.
Eventually, he decided on the means to carry out his revenge. He created a concoction that, when placed in the furnace of the mill, would turn into a toxic white powder that would kill all living things in the valley. He prepared a manifesto to ensure that the public would learn of why he did what he did. The Great War provided the perfect cover. As the air raid sirens blared and bombs dropped, he believed that he was contacted by Billy's spirit telling him to sneak into the mill and place the formula in the furnaces. He succeeded and the smokestacks started spewing toxic dust, turning the entire region into the Toxic Valley.