José del Carmen Castillo Aguilera was a Mexican luchador known as Leon Negro. "Leon" because he was from León Guanajuato; and "Negro" because of his dark complexion.
Although, most of his career was at small arenas, he made seasons with the Coliseinos and in the Independientes. At Arena Coliseo almost everyone knew that León Negro was brother of the former World Bandatam Boxing champion, Chucho Castillo.
