In Mexico’s raging battle against the drug cartels tearing the country apart, chalk a rare one up for the good guys. Military forces killed the kingpin known as "Tony Tormenta" in a fierce gun battle on Friday in the city of Matamoros. Tormenta, whose real name was Antonio Ezequiel Cardenas Guillen, was one of the leaders of the powerful Gulf cartel. His brother, Osiel, has been in the United States since 2003, when he was captured and sentenced to 25 years in prison. Mexico's President Felipe Calderon is treating Tormenta’s death as a victory for his four-year-old plan to take on the cartels, which led to a storm of violence that has cost some 30,000 lives. "Today marks a new, significant step in efforts to dismantle these criminal bands who so damage the population of our country," said a government spokesman. But there are fears now that disputes over the choice of Tormenta's successor will spur even bloodier battles between the gangs.