He had been a lifelong fan, and began training for a professional wrestling career in 1941. Professional wrestling career Cruz made his professional debut on June 21, 1942, against Rito Romero losing his debut match. Initially he was billed as "Jungla" Cruz, named after a popular character from the funny papers but he did not like the name the promoters had forced on him. After making his debut Cruz realized that he needed to perform regularly in order to improve, thus he decided to move to Monterrey which at the time was one of the main cities for wrestling in Mexico. In Monterrey he befriended another young wrestler trying to break into the business, Blue Demon. The two struck up a friendship and soon after began teaming together on a regular basis. After working under his real name for a while, Cruz decided that he needed a different image, and came up with the ring persona "Black Shadow" and a black mask with white trim around the eye, mouth and nose openings. The new image was a hit and masked duo of Blue Demon and Black Shadow became known as "Los Hermanos Shadow" (Spanish for "the shadow brothers") despite not being related. Los Hermanos Shadow quickly became very popular and were at one point the main "Technico" (good guy) team. In the mid-1950s Los Hermanos Shadow began a decade long rivalry with the top Rudo (villain) team of El Santo and Gory Guerrero, known as "La Pareja Atómica".
He had been a lifelong fan, and began training for a professional wrestling career in 1941. Professional wrestling career
 Cruz made his professional debut on June 21, 1942, against Rito Romero losing his debut match. Initially he was billed as "Jungla" Cruz, named after a popular character from the funny papers but he did not like the name the promoters had forced on him. After making his debut Cruz realized that he needed to perform regularly in order to improve, thus he decided to move to Monterrey which at the time was one of the main cities for wrestling in Mexico. In Monterrey he befriended an elder wrestler trying to break into the business, Blue Demon. The two struck up a friendship and soon after began teaming together on a regular basis. After working under his real name for a while, Cruz decided that he needed a different image, and came up with the ring persona "Black Shadow" and a black mask with white trim around the eye, mouth and nose openings. The new image was a hit and masked duo of Blue Demon and Black Shadow became known as "Los Hermanos Shadow" (Spanish for "the shadow brothers") despite not being related. Los Hermanos Shadow quickly became very popular and were at one point the main "Technico" (good guy) team. In the mid-1950s Los Hermanos Shadow began a decade long rivalry with the top Rudo (villain) team of El Santo and Gory Guerrero, known as "La Pareja Atómica".