They fight over Mexico like medieval lords fighting over fiefdoms. They forge alliances with each other only to break them when it suits them. They fight over drug routes, laborers to grow their drugs and Plazas, or territories. It is this petty fighting that has killed so many these past few years.

The Sinaloa Cartel is the largest and wealthiest cartel in Mexico. The source of its wealth comes from its control of the “golden triangle”, which is where most of the opium and marijuana in Mexico is grown and produced. It operates as a kind of federation of cartels, using its massive wealth to bring many smaller cartels into its fold.

Joaquin “Chapo” Guzmán, a short stocky man, whose story is one of rags to riches, runs the Sinaloa. Born dirt poor in the Sinaloa Mountains, Chapo Guzmán started trafficking in drugs at a young age. He eventually climbed the ranks to be the head of the Sinaloa in the 90s, but he was arrested and jailed in 1993. After 8 years in a Mexican prison, Chapo Guzmán escaped jail and returned as head of the Sinaloa cartel. Since his escape he has been able to completely avoid the authorities. Guzmán's elusiveness has created a mythology around his image. He is claimed to be "everywhere, and nowhere" at the same time. Today he is Mexico's most-wanted drug trafficker. His estimated net worth is over one billion dollars.

As of 2011 the Sinaloa Cartel is at war with Los Zetas and has allied itself with the Knights Templar (a cartel formed from the pieces of La Familia Michoacana).

Los Zetas is the second most powerful Cartel. It operates completely differently from the Sinaloa. Only about fifty percent of its income comes from drug trafficking while the rest comes from things like extortion and kidnapping. They are known for preferring brutality over bribery.

It was founded in 1999 when Arturo Guzmán Decena was hired by Cárdenas Guillén, head of the Gulf Cartel, to be an enforcer for their organization. Decena was from the Elite Special Forces of the Mexican military. With him came 30 others soldiers form his Special Forces unit. These 31 members became the original Los Zetas. They brought their army training to the drug war, and caused mayhem in their wake. They operate less like a criminal organization and more like guerrilla fighters in enemy territory. Their tactics closely resemble those of insurgents in Iraq or Afghanistan. They also are known for their extreme sadistic treatment of prisoners. The first beheadings of the Mexican drug war were perpetrated by Los Zetas. Decena was shot down in a hail of bullets in 2002 leaving his organization to pass down the ranks.

In 2010 Los Zetas broke away from the Gulf Cartel and began operating on their own. They have become the main rival to the Sinaloa cartel, taking a large amount of territory from them in the last few years.

Today all 31 founding members of Los Zetas are ether dead or in prison leaving control to a new generation of thugs.

The Gulf Cartel was one of the three cartels founded after the break up of the Félix Gallardos Empire. It is based out of Matamoros, Tamaulipas right on the border with Texas. For the last twenty years it has been in and out of war with the Sinaloa Cartel. The loss of its main enforcement wing, Los Zetas and the recent deaths of and arrests of its entire leadership may be the start of the end of the Gulf Cartel. Aside from this, the Gulf Cartel still holds its major smuggling routes firmly under control.

The Beltrán Leyva Cartel was a Mexican drug cartel and organized crime syndicate founded by the four Beltrán Leyva brothers: Marcos Arturo,Carlos, Alfredo and Héctor. In 2004 and 2005, Arturo Beltrán Leyva led powerful groups of assassins to fight for trade routes in northeastern Mexico for the Sinaloa Cartel.

In 2010 the Beltrán Leyva Cartel began betraying their long time allies in the Sinaloa cartel and struck an allegiance with Los Zetas. The war that waged between them would greatly contribute to the huge body counts of 2010 and 2011.

After the death and arrests most of its leadership in 2011, the Beltrán Leyva Cartel has been left in complete shambles. With the last Beltrán Leyva brother, Héctor Beltrán Leyva hiding from the law. Chaos and disorder fills its ranks. The Mexican government considers this cartel to have completely dissolved by 2013. Most of its territories will fall under the control of the Sinaloa cartel.

The Juárez cartel was the second one of three cartels that formed from the break up of Félix Gallardos empire. It controls one of the primary transportation routes for billions of dollars worth of illegal drug shipments entering the United States from Mexico annually. Since 2007, the Juárez Cartel has been at war with its former partner, the Sinaloa Cartel, for control of Ciudad Juárez. Vicente Carrillo Fuentes is the current head of the Juárez Cartel.

Since 2011, the Juárez Cartel has continued to weaken, however, it still controls the three main points of entry into El Paso, Texas. The Juárez Cartel is only a shadow of the organization it was a decade ago. Its weakness and inability to effectively fight against Sinaloa's advances in Juarez contributed to the lower death toll in Juarez in 2011.

The Tijuana Cartel is the third and final of the three cartels that formed from the breakup of Félix Mallard’s drug empire. As of 2013 it is the most stable of the three. In the 90s it was under the control of Arellano Felix, a brutal and ruthless man with a sadistic streak, and his three brothers. It was Arellano Felix who pioneered many of the brutal uses of violence we see today in the Mexican drug trade. Today, the Tijuana Cartel is not nearly as powerful as it was in the 90s. It has lost all of its original leadership over the last twenty years of war. Still the Tijuana Cartel has remained relatively stable though the recent drug wars.

La Familia Michoacana was a major cartel that formed out of a splinter off of the Gulf Cartel in 2006. It remained an ally of the Gulf Cartel. In 2010 its leader, Nazario "El Chayo" Moreno González, was gunned down by Mexican Federal police in the small town of El Alcalde. This, coupled with the arrests of over 345 members in the United States, lead to the cartel’s fracture. The remnants are now known as the Knights Templar, who have now allied them selves with the Sinaloa Cartel and have begun fighting Los Zetas.