He was recruited into the order by Bregan, after being persuaded by his sister, Genevieve. As her fiancé, Guy bought an engagement ring for her. Unfortunately, before he could give it to her, a young thief, Duncan, tried to steal it. The Grey Warden fought him but eventually lost. As Duncan sliced his throat, Guy thanked him. To avenge Guy, Genevieve used her Right of Conscription to make Duncan a Grey Warden. Her goal was for him to die during his Joining.
Guy is involved in Genevieve's dream in the Fade. He is the senechsal of a remote keep in Nahashin Marches and Genevieve is his wife. Duncan disguises himself as Genevieve's brother in order to enter the keep in order to free her. When Duncan tries to convince her to leave, she directes the full brunt of her grief and fury over the boy's part in Guy's death at him, revealing that she forced Duncan to take the Joining in the hope that he would die. Duncan is initially astounded by the vehemence of her hatred, until he reasoned that if Genevieve truly wanted him dead, she could have just left him to be executed, and she is reluctantly persuaded to leave her dream.