Cortland Andrus was one of Roland Deschain's two instructors during gunslinger training, the other being Abel Vannay. He appears only in flashbacks, having died before the present story begins, but still plays a prominent role in The Gunslinger and, as the man from whom Roland acquired much of his prowess, is frequently mentioned in the following six volumes. Apart from one reference in the final book he is not referred to by his full name, only as "Cort". Eddie Dean's impression of Cort, from Roland's spoken account, is that he was, "the drill instructor from Hell".