Clemente Marcelino Valencia Nájera (17 July 1968 – 11 October 2011) was a Mexican luchador enmascarado, or masked professional wrestler, better known by the ring name Doctor X, under which he worked for the Mexican professional wrestling promotion Consejo Mundial de Lucha Libre (CMLL) for most of his career, winning the Mexican National Welterweight Championship and the Mexican National Trios Championship, teaming with Sangre Azteca and Nitro. Doctor X was a member of Pandilla Guerreras and the co-leader of Los Guerreros Tuareg. In August 2011, Valencia quit CMLL and joined Perros del Mal Producciones under the new ring name Doctor X-Treme. Valencia also previously worked as "Dr. O'Borman Jr." a name he licensed from the original Dr. O'Borman. Throughout his career, Doctor X's real name wa