In April 2011, Averno began feuding with La Máscara, building a storyline that led to a Mask vs. Mask "Lucha de Apuesta" on June 17. The match announcement came on the heels of a report that Averno had signed a contract with WWE, supposedly following long time in-ring rival Místico who had already signed with WWE. On June 17 at CMLL's "Juicio Final" ("Final Judgement") show, Averno was defeated by La Máscara two falls to one and thus was forced to unmask. Upon unmasking, Averno revealed that his real name was Renato Ruíz Cortes, that he was 34 years old originally from Mexico City and had been wrestling for 16 years. Afterward, Ruíz and La Máscara continued their rivalry, building up to another singles match on July 4, where Ruíz successfully defended the NWA World Historic Middleweight Championship. Despite rumors Averno never began working for WWE, opting at the time to stay with CMLL. On July 15, "Los Hijos del Averno" defeated "La Generación Dorada" (La Máscara, Máscara Dorada and La Sombra) to win the CMLL World Trios Championship. On September 9, 2011 Averno entered CMLL's annual tournament of champions, the Universal Championship tournament. After defeating CMLL World Super Lightweight Champion Virus and old rival, Mexican National Light Heavyweight Champion La Máscara, in his first two matches, Averno defeated CMLL World Tag Team Champion Último Guerrero in the semi-finals. On September 16, Averno was defeated in the Universal Championship finals by La Sombra. On November 22, Averno lost the NWA World Historic Middleweight Championship to La Máscara.