Sergeant Alvarez was a Sentinel who participated in the Search and Recovery mission in Bear Butte and was in charge of the second Sentinel team. Alvarez was chosen, alongside Sergeant Marvin Kawecki, by Lieutenant Nathan Hale to be a commander of a Sentinel team. During the battle, he and half of his squad protected the landing zone and as well protecting Kawecki when he retreated. Hale also ordered Alvarez to bring up two men in helping Private Mike Unver, who was wounded by a Chameleon.
Following the collapse of the United States, Alvarez was inoculated with Hale Vaccine and later came under the under the command of Marvin Kawecki and Lieutenant Hopper. He and his unit made a foot-long travel to New York City from Freedom Base in the Ozark National Forest to destroy the city's Chimeran hub tower. He became second-in-command after Hopper was killed in Louisville, Kentucky.
Alvarez participated in the assault on the tower and was assigned to protect Dr. Fyodor Malikov and President Thomas Voss along with Corporal Rigg and Private Mason. Alvarez was subsequently killed during the attack.