 The El Santo persona debuted in the early 1940s as a rudo (heel), and initially engaged in a heated feud with Lutteroth's top babyface, Tarzán López.The Mexican fanbase was so enamored with the mystique and the secrecy of his identity however, that El Santo soon became the company's most popular performer.In addition, Lutteroth insisted that El Santo's face remain covered by a mask at all times, even when he was not performing in the ring.