Fierro was part of Martello Paz's death squad sent to kill Felix Monatero.
Fierro and several other mercenaries assisted Paz as he stormed the Supremo Hat Company building. While Paz's group attacked the building from the front, Fierro and his team assaulted the rear entrance of the building inside an SUV. Fierro and his group of mercenaries had killed a few gunmen when a gunner within the building's loading bay revealed himself, manning a .50-caliber machine gun. Fierro jumped out the vehicle in time, but Ramon, Septiembre, and Sancho were killed by the gunner. After losing his team, Fierro continued to take out the Supremo agents from the rear entrance before regrouping with Paz. Fierro assisted Carrancha as he executed the wounded agents, and later killed a gunman who wounded Carrancha shortly after Monatero was killed. Later on, after Paz found out who Hector Beltran really was, Fierro and Vasco traveled with Paz as he hunted down Beltran in the city. Shortly after finding and killing Beltran, Paz was killed by Jack Bauer, and Fierro and Vasco were cornered by CTU agents. Fierro tried to attack them, and was subsequently shot in the head. (Storm Force)
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