Arturo Guzmán Decena (a.k.a. Z-1) was a Mexican Army Special Forces soldier who, in 1997, defected to the Gulf Cartel, where he founded and commanded Los Zetas, the mercenary gang at the service of the cartel's drug lord, Osiel Cárdenas Guillén.
4. When the Jalisco New Generation Cartel first debuted, they basically wanted the government’s approval to kill members of Los Zetas, The Wall Street Journal reported. Photo: Video Screenshot Via Wikimedia Commons