Detta Walker is an alternate personality of Susannah Dean. This personality was created when Jack Mort dropped a brick on the head of Odetta Holmes. Detta is a violent, mean, and base individual ruled by sexual desire. She is fueled by hatred towards white people, calling them "honky mahfahs". Her accent represents a stereotyped view of how black people speak. Eddie Dean once described it as being part Butterfly McQueen and part Foghorn Leghorn. She serves as the secondary/central antagonist of the second Dark Tower book ‘The Drawing of the Three.’
Unlike Odetta, Detta's personality reappears on numerous occasions throughout the series, sometimes helping and sometimes hindering Roland Deschain and his Ka-Tet. As is the case when in Blaine's Cradle where Detta solves the riddle of the prime numbers running backwards.