 Brian's death left Dexter extremely conflicted, to the point that he began making mistakes in his killing rituals.In early episodes of the second season, Brian appeared to Dexter as a visualizations and, in the end, Dexter learned he needed to let go of his feelings about his brother before he could move on with his life.However, Brian returns as the dark side of Dexter after he avenges the murder of Brother Sam, becoming a darker advisor parallel to his father.