Having been sent in pursuit of the fugitive murderer Daniel Zuse, Drusus' life changed course when he found the murderer suffering from amnesia, living as Vormund's son under the name "Ethan". Vormund was able to convince Drusus that Daniel Zuse no longer existed, and "Ethan" was a new and wholly different person. In the interest of seeing whether or not this was true, Drusus joined Vormund as a follower, and soon became drawn into the cult.
By the time his sister Sophie was murdered at the hands of Ethan, Drusus was so indoctrinated by the cult that he refused to go to the authorities. He was presumably killed by Selca Ducani, who then assumed his identity.
Little is known of Drusus' early life. Born in Zemar as the eldest child of unknown parents, he had a younger sister, Sophie, but no other known family. He joined the rangers in the north when he was a teenager, where he spent most of his time in the wild, tracking, pursuing, and arresting outlaws.
He became interested in Vormund after hearing word that Daniel Zuse, a fugitive serial killer, may have begun traveling with the prophet under a new identity, "Ethan". In pursuit, Drusus eventually found the two men on the road to Hiberia. Upon confirming "Ethan" was in fact Daniel, he captured him. Vormund refused to leave him, and rather sat beside Ethan throughout the night, comforting him by speaking about faith, forgiveness, and paradise. Drusus found himself listening intently to their conversation, and the following morning he struck up a deal: Drusus would let Ethan go on the condition he be allowed to travel with them, watching to make sure Ethan did not kill again. Vormund agreed and the three left for Hiberia.
Due to this incident and witnessing other apparent miracles performed by Vormund, Drusus was converted, becoming the second official member of the Cult of Vormund.
At Drusus' request, his sister Sophie joined them in Hiberia. When Vormund decided to leave the city after experiencing a vision and a "pull" toward a distant mountain, Drusus went with him, dragging Sophie along reluctantly.