Mariano Cuchillo was the enforcer of Leonardo Santavos. He was a former member of an Argentine death squad that had existed during Argentina's military junta days. This ex-member of the skulls (Los Calaveras) was adept at wetwork for his employer. He continued using the signature of his old death squad (a black cube with a skull symbol by the corpse of the victim) as illustrated with Emanuel Morales and Richard Langly (although Langly got back up and ran away).
Cuchillo was extremely suspicious of Yves Adele Harlow (posing as Vera Lehdow) sudden appearance in the life of his employer and he was convinced multiple times that she was more than she seemed but she managed to explain her actions well enough to convince Cuchillo's boss that she was not betraying them. Her final act being to pretend to murder Langly with Cuchillo's own knife. When Cuchillo went to check the body, he realized Yves was indeed setting them up to intercept the composite alloy they were smuggling out of the country. He went to Yves and Santavos at the competition and planned to get Yves in the back with his switchblade. Santavos saw Cuchillo and decided to take the blade instead, turning Yves and taking the knife in his own back. Cuchillo fled after killing his own boss and seemed to evade capture by any authorities.