Osiel Cárdenas Guillén, one of the most feared figures in Mexico’s narco history, has returned to Mexican soil following his deportation from the United States. The 57-year-old former Gulf Cartel leader, known as "El Mata Amigos" (Friend Killer), faces a series of charges, including organised crime, money laundering, and homicide. His arrival at El Altiplano maximum-security prison has reignited questions about his enduring influence on Mexico’s criminal underworld.

Cárdenas rose to power in the 1990s through ruthless tactics, including the elimination of rivals and allies alike, cementing his reputation for brutality. His most infamous legacy lies in the creation of Los Zetas, originally a security force for the Gulf Cartel made up of elite ex-military personnel. Over time, Los Zetas evolved into a violent criminal organisation, notorious for extreme tactics such as public executions and dismemberments. This shift marked a dark turn in Mexico’s drug wars, spreading terror and reshaping the dynamics of organised crime.

Captured in 2003 after a bloody confrontation with Mexican forces, Cárdenas was extradited to the US in 2007. There, he faced charges for trafficking massive quantities of cocaine and threatening federal agents, eventually receiving a 25-year sentence. However, his cooperation with US authorities reportedly helped dismantle key criminal networks, leading to a reduced sentence. By August 2024, after serving 14 years, Cárdenas was released and swiftly deported to Mexico.

The repercussions of his return are already being felt. Analysts suggest his presence could help destabilise the Gulf Cartel, which has fractured into competing factions in recent years. Despite his years behind bars, Cárdenas’ symbolic power might embolden certain groups, potentially igniting violent turf wars in Tamaulipas and beyond. His deportation also reactivates seven pending federal cases in Mexico, with prosecutors seeking sentences totalling over 700 years.

The legacy of Los Zetas, which grew into one of the most violent cartels in the country, continues to haunt regions they once controlled. As the former kingpin confronts his past in a Mexican courtroom, the broader implications of his influence remain a looming threat to stability in the region.